Big Ideas Math Answers Grade 1 Chapter 2

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10

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Big Ideas Math Book 1st Grade Answer Key Chapter 2 Fluency and Strategies within 10

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Vocabulary

Lesson 1: Add 0

Lesson 2 Subtract 0 and Subtract All

Lesson 3: Add and Subtract 1

Lesson 4: Add Doubles from 1 to 5

Lesson 5: Use Doubles

Lesson 6: Add in Any Order

Lesson 7: Count on to Add

Lesson 8: Count Back to Subtract

Lesson 9: Use Addition to Subtract

Performance Task

Fluency and Strategies within 10 Vocabulary

Organize It

Review words:
addend
sum
difference

Use the review words to complete the graphic organizer.

Question 1.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 1
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10Fluency-Strategies-within-10-Vocabulary-Question-1
Explanation:
A number that is added to another number is known as an addend.
In this case, 3 and 4 are the addends.
Sum is the result of adding two numbers.
So, 3 + 4 = 7
7 is the result that means sum.

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 2
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10Fluency-Strategies-within-10-Vocabulary-Question-2

Define It

Use your vocabulary cards to match.

Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 3
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10Fluency-Strategies-within-10-Vocabulary-Define-it

Explanation:
A number line can be defined as a straight line with numbers placed at equal intervals or segments along its length. A number line can be extended infinitely in any direction and is usually represented horizontally.
Count on is nothing the count that goes forward.
Count back is nothing but count that goes backward.

Lesson 2.1 Add 0

Explore and Grow

Use linking cubes to model each story.

There are 6 ducks in the pond. 0 ducks join them. How many ducks are in the pond flow?

____ ducks

Answer:
Number of ducks in pond = 6
Number of ducks joined= 0
Total number of ducks= 6+0=6 Ducks

Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 4
Answer:
Number of ducks in pond = 0
Number of ducks joined= 8
Total number of ducks= 0+8=8 ducks

Show and Grow

Use the picture to write an equation.

Question 1.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 5
Answer:
4 + 0 = 4

Explanation:
By seeing the above picture we say that one of the addend is 4 and another addend is 0.
Now add both the numbers
4 + 0 = 4
Thus the result is 4.

Question 2.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 6
Answer:
0 + 1=1
Explanation:
From the above figure we notice 0 and 1 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 1 = 1
Thus the result is 1.

Question 3.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 7
Answer:
0 + 6 = 6
Explanation:
From the above figure we notice 0 and 6 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 6 = 6
Thus the result is 6

Question 4.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 8
Answer:
8 + 0 = 8
Explanation:
From the above figure we notice 0 and 8 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
8 + 0 = 8
Thus the result is 8.

Apply and Grow: Practice

Use the picture to write an equation.

Question 5.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 9
Answer:
7 + 0 = 7
Explanation:
From the above figure we notice 0 and 7 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
7 + 0= 7
Thus the result is 7.

Question 6.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 10
Answer:
0 + 10 = 10
Explanation:
From the above figure we notice 0 and 10 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 10 = 10
Thus the result is 10.

Question 7.
9 + 0 = _____
Answer:
9 + 0 = 9
Explanation:
From the above figure we notice 0 and 9 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
9 + 0 = 9
Thus the result is 9.

Question 8.
0 + 8 = ______
Answer:
0 + 8 = 8
Explanation:
From the above figure we notice 0 and 8 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 8 = 8
Thus the result is 8.

DIG DEEPER!
Find each sum. Think: What do you notice?

Question 9.
3 + 0 = ______
0 + 3 = ______
Answer:
3 + 0 = 3
0 + 3 = 3
We notice that any number added with 0 will be the same number.

Question 10.
0 + 6 = ______
6 + 0 = ______
Answer:
0 + 6 = 6
6 + 0 = 6
We notice that any number added with 0 will be the same number.

Question 11.
MP Logic
There are 7 penguins in all. How many penguins are inside the igloo?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 11
Answer:
Total Number of penguins = 7
Number of penguins outside = 7
Number of penguins inside = x
x + 7 = 7
x = 0

Think and Grow: Modeling Real Life

There are no students at a bus stop. Then 9 students arrive. How many students are at the bus stop now?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 12
Model:
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 13
Addition equation:

_________ students
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.1-Add-0-Think-Grow
0 + 9 = 9
Number of students at bus stop = 9 students
Explanation:
From the above figure we notice 0 and 9 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 9 = 9
Thus the result is 9.

Show and Grow

Question 12.
Your friend does not have any tokens. You give your friend 7 tokens. How many tokens does your friend have now?
Model:
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 14
Addition equation:

__________ tokens
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.1-Add-0-Show-Grow-Question-12
0 + 7 = 7
Number of tokens with my friend = 7 tokens
Explanation:
From the above figure we notice 0 and 7 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 7 = 7
Thus the result is 7.

Add 0 Practice 2.1

Use the picture to write an equation.

Question 1.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 15
________ + 0 = _________
Answer:
9 + 0 = 9
Explanation:
From the above figure we notice 0 and 9 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
9 + 0 = 9
Thus the result is 9.

Question 2.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 16
________ + 0 = _________
Answer:
0 + 3 = 3
Explanation:
From the above figure we notice 0 and 3 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 3 = 3
Thus the result is 3

Question 3.
10 + 0 = ________
Answer:
10 + 0 = 10
Explanation:
From the above figure we notice 0 and 10 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
10 + 0 = 10
Thus the result is 10.

Question 4.
0 + 5 = _______
Answer:
0 + 5 = 5
Explanation:
From the above figure we notice 0 and 5 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 5 = 5
Thus the result is 5.

Question 5.
0 + 6 = _______
Answer:
0 + 6 = 6
Explanation:
From the above figure we notice 0 and 6 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 6 = 6
Thus the result is 6.

Question 6.
0 + 0 = _______
Answer:
0 + 0 =0
Explanation:
From the above figure we notice 0 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 0 = 0
Thus the result is 0.

Question 7.
DIG DEEPER!
Find each sum. Think: What do you notice?
7 + 0 = ______
0 + 7 = ______
Answer:
7 + 0 = 7
0 + 7 = 7
Explanation:
From the above figure we notice 0 and 1 are addends . Adding 0 to any number gives the sum as the number itself. If the order of the addends changes, the sum stays the same.Now add both the numbers
0 + 1 = 1
Thus the result is 1.

Question 8.
MP Logic
There are 8 students in all. How many students are inside the museum?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 17
Answer:
Number of students = 8
Number of students out side the museum= 8
Number of students inside the museum=  x
x + 8 = 8
x = 0
Number of students inside the museum = 0

Question 9.
Modeling Real Life
There are no seals on the shore. Then 10 seals swim to the shore. How many seals are on the shore now?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 18
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 19

__________ seals
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-0-Practice-2.1-Question-9
0 + 10 = 10
Number of seals on the shore = 0 + 10 = 10 seals
Explanation:
From the above figure we notice 0 and 10 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
0 + 10 = 10
Thus the result is 10.

Review & Refresh

Write the number of goldfish.

Question 10.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 20
Answer:
1
Explanation:
As per above figure we notice only 1 goldfishes in the aquarium.

Question 11.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 21
Answer:
3
Explanation:
As per above figure we notice 3 goldfishes in the aquarium.

Question 12.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 22
Answer:
0
Explanation:
As per above figure we notice no goldfish in the aquarium.

Question 13.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 23
Answer:
2
Explanation:
As per above figure we notice 2 goldfishes in the aquarium.

Lesson 2.2 Subtract 0 and Subtract All

Explore and Grow

Use linking cubes to model each story.

There are 5 beavers on the log. None of the beavers leave. How many beavers are left?

________ beavers
Answer:
Number of beavers = 5
Number of beavers leave= 0
Number of beavers Remaining = 5 – 0 = 5

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 24
There are 5 beavers on the log. All of the beavers leave. How many beavers are left?

_________ beavers

Answer:
Number of beavers = 5
Number of beavers left = 5
Number of beavers remaining =5 – 5 = 0

Show and Grow

Use the picture to write an equation.

Question 1.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 25
_________ – 0 = ________
Answer:
2 – 0  = 2
Explanation:
From the above equation we notice 2 is minuend and 0 is subtrahend. Subtracting 0 from any number gives the number itself as the difference. Now subtract the 2 and 0
2 – 0 = 2
Thus the difference is 2

Question 2.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 26
_________ – _________ = 0
Answer:
1 – 1 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 3.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 27
_________ – 0 = _________
Answer:
4 – 0 = 4
Explanation:
From the above equation we notice 4 is minuend and 0 is subtrahend. Subtracting 0 from any number gives the number itself as the difference. Now subtract the 4 and 0
4 – 0 = 4
Thus the difference is 4

Question 4.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 28
_________ – _________ = 0
Answer:
2 – 2 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Apply and Grow: Practice

Use the picture to write an equation.

Question 5.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 29
_________ – 0 = _________

Answer:
8 – 0 = 8
Explanation:
From the above equation we notice 8 is minuend and 0 is subtrahend. Subtracting 0 from any number gives the number itself as the difference. Now subtract the 2 and 0
8 – 0 = 8
Thus the difference is 8

Question 6.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 30
_________ – _________ = 0
Answer:
8 – 8 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 7.
5 – 5 = _______
Answer:
5 – 5 = 0

Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 8.
6 – 0 = ________
Answer:
6 – 0 = 6
Explanation:
From the above equation we notice 6 is minuend and 0 is subtrahend Subtracting 0 from any number gives the number itself as the difference. Now subtract the 6 and 0
6 – 0 = 6
Thus the difference is 6

Question 9.
9 – 0 = ________
Answer:
9 – 0 = 9
Explanation:
From the above equation we notice 9 is minuend and 0 is subtrahend Subtracting 0 from any number gives the number itself as the difference. Now subtract the 9 and 0
9 – 0 = 9
Thus the difference is 9

Question 10.
7 – 7 = ________
Answer:
7 – 7 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 11.
MP Structure
Complete the equation. Then use the words to complete the sentence.

Words:
difference
number
subtract

4 – ______ = 4
When you ______ 0 from a number,  the ______ is that ______ .
Answer:
4 – 0 = 4
When you subtract 0 from a number,  the number is that difference.

Think and Grow: Modeling Real Life

Your friend has 7 pennies. You have 7 fewer pennies than your friend. How many do you have?
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 31
Draw a picture:

Subtraction equation:

_________ pennies
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson -2.2-Subtract-0-Subtract-All-Think-Grow-Modeling-Real-Life
Number of pennies with my friend = 7
Number of pennies with me  = x
x = 7 – 7 (7 fewer than my friend )
x = 0
Number of pennies with me = 0

Show and Grow

Question 12.
You have 6 pieces of chalk. You give all of your chalk to your friend. How many pieces do you have left?
Draw a picture:

Subtraction equation:

_________ pieces of chalk
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson -2.2-Subtract-0-Subtract-All--Show-Grow-Question-12
Number of chalks with me = 6
Number of chalks given to my friend = 6
Number of chalks remaining with me = 6 – 6 = 0

Subtract 0 and Subtract All Practice 2.2

Use the picture to write an equation.

Question 1.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 32
________ – 0 = ________
Answer:
5 – 0 = 5

Question 2.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 33
________ – _______ = 0
Answer:
5 – 5 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 3.
3 – 3 = _______
Answer:
3 – 3 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 4.
1 – 0 = _________
Answer:
1 – 0 = 1

Question 5.
1 – 1= _________
Answer:
1 – 1= 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 6.
7 – 0 = _________
Answer:
7 – 0 = 7

Question 7.
MP Structure
Complete the equation. Then use the words to complete the sentence.

Words:
difference
number
subtract

9 – ______ = 0
When you ______ a ______ from itself, the ______________ is 0.

Answer:
9 – 9 = 0
When you subtract a number from itself, the difference is 0

Question 8.
Modeling Real Life You have 4 stuffed animals. You give all of them to your friend. How many stuffed animals do you have left?
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 34

________ stuffed animals

Answer:
Number of stuffed animals  with me = 4
Number of stuffed animals given to my friend= 4
Number of stuffed animals remaining = 4 – 4 = 0

Review & Refresh

Write the number of dots you see on each domino. Then write the numbers in order.

Question 9.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 35
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Subtract-0-Subtract-All-Practice-2.2-Question-9

Question 10.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 36
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Subtract-0-Subtract-All-Practice-2.2-Question-10

Lesson 2.3 Add and Subtract 1

Explore and Grow

Use linking cubes to model each story.

There are 7 kids on the bench. 1 kid joins them. How many kids are on the bench flow?
__________ kids

Answer:
Number of kids = 7
Number of kids joined = 1
Total number of kids = 7 + 1 = 8
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 37
There are 8 kids on the bench. 1 kid leaves. How many kids are left?
__________ kids

Answer:
Number of kids = 8
Number of kids left = 1
Total number of kids = 8 – 1 = 7

Show and Grow

Use the picture to write an equation.

Question 1.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 38
___________ – __________ = ___________
Answer:
7 – 1 = 6
Explanation:
From the above figure, we notice six people are playing and one person is leaving . so we get equation as
6 + 1 = 7 .
In Total we notice 7 people in the picture .

Question 2.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 39
___________ + __________ = ___________
Answer:
7 + 1 = 8
Explanation:
From the above figure, we notice 7 people are playing and 1 person is joining. so we get equation as
7 + 1 = 8 .
In Total we notice 8 people in the picture .

Apply and Grow: Practice

Use the picture to write an equation.

Question 3.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 40
___________ + __________ = ___________
Answer:
9 + 1 = 10
Explanation:
From the above picture we notice 9 people in the pool and 1 person is joining the pool. so total number of people in pool is 9 + 1 = 10 .
Thus Total people in the pool are 10 people.

Question 4.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 41
___________ + __________ = ___________
Answer:
8 + 1 = 9
Explanation:
From the above picture we notice 8 people in the pool and 1 person is leaving the pool. so total number of people in the picture is 8 + 1 = 9 .
Thus Total people are 9 people.

Question 5.
5 – 1 = ________
Answer:
5 – 1 = 4
Explanation:
From the above equation we notice 5 is minuend and 1 is subtrahend.
Now subtract
5 – 1 = 4
Thus the difference is 4

Question 6.
6 + 1 = ________
Answer:
6 + 1 = 7
Explanation:
From the above figure we notice 6 and 1 are addends .Now add both the numbers
6 + 1 = 7
Therefore the sum is 7.

Question 7.
8 + 1 = ________
Answer:
8 + 1 = 9
Explanation:
From the above figure we notice 8 and 1 are addends .Now add both the numbers
8 + 1 = 9
Therefore the sum is 9.

Question 8.
7 – 1 = ________
Answer:
7 – 1 = 6
Explanation:
From the above equation we notice 7 is minuend and 1 is subtrahend.
Now subtract
7 – 1 = 6
Thus the difference is 6

DIG DEEPER!
Circle the problem with the greater sum or difference.
Question 9.
2 – 1                2 + 1
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.3-Add-Subtract-1-Question-9
Explanation:
from above equations we get
2 – 1 = 1 as difference and
2 + 1 = 3 as sum
now compare difference and sum
1 < 3
Therefore , 3 is greater than 1

Question 10.
5 + 1              6 – 1
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.3-Add-Subtract-1-Question-10
Explanation:
from above equations we get
6 –  1 = 5 as difference and
5 + 1 = 6 as sum
now compare difference and sum
6 > 5
Therefore , 6 is greater than 5

Question 11.
YOU BE THE TEACHER
Circle to show who is correct. Show how you know?
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.3-Add-Subtract-1-Question-11
Explanation:
when a given number is increased by 1 then we get the next number of that number, Also, we know that a next number of a number is called successor.
From the number line we can notice when 3 is added with 1 we get 4 as sum which is next number of 3.

Think and Grow: Modeling Real Life

You have 9 action figures. Newton has 1 more than you. Descartes has 1 fewer than you. Who has more, Newton or Descartes?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 43

Equations:            Newton            Descartes

Who has more    Newton           Descartes
Answer:
Number of action figures with me= 9
Number of action figures with Newton = 9 + 1 = 10
Number of action figures with Descartes = 9 – 1 = 8
Newton has 2 more action figures than Descartes.

Show and Grow

Question 12.
You have 5 video games. Newton has 1 fewer than you. Descartes has 1 more than you. Who has fewer, Newton or Descartes?
Equations:            Newton            Descartes

Who has fewer?    Newton           Descartes
Answer:
Number of video games with me = 5
Number of video games with Newton  = 5 – 1 = 4
Number of video games with Descartes = 5 + 1 = 6
Newton has 2 fewer than Descartes.

Add and Subtract 1 Practice 2.3

Use the picture to write an equation.

Question 1.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 44
___________ + ___________ = ___________
Answer:
5 + 1 = 6
Explanation:
From the above equation we notice 5 and 1 are addends .when a given number is increased by 1 then we get the next number of that number as sum, next number of 5 is 6
Now add both the numbers
5 + 1 = 6
Therefore the sum is 6.

Question 2.

___________ – ___________ = ___________
Answer:
5 – 1 = 4
Explanation:
when a number is reduced by 1, then we get the previous number of that number as difference.
previous number of 5 is 4 .
Therefore difference = 4

Question 3.
10 – 1 = ___________
Answer:
10 – 1 = 9
Explanation:
when a number is reduced by 1, then we get the previous number of that number as difference.
previous number of 10 is 9 .
Therefore difference = 9

Question 4.
7 + 1 = ___________
Answer:
7 + 1 = 8
Explanation:
From the above Equation we notice 7 and 1 are addends .when a given number is increased by 1 then we get the next number of that number as sum, next number of 7 is 8
Now add both the numbers
7 + 1 = 8
Therefore the sum is 8.

DIG DEEPER!
Circle the problem with the greater sum or difference.
Question 5.
4 – 1 4 + 1
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Subtract-1-Practice-2.3-Question-5
Explanation:
from above equations we get
4 – 1 = 3 as difference and
4 + 1 = 5 as sum
now compare difference and sum
3 < 5
Therefore , 5 is greater than 3

Question 6.
7 + 1 8 + 1
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Subtract-1-Practice-2.3-Question-6
Explanation:
from above equations we get
7 + 1 = 8 as sum and
8 + 1 = 9 as sum
now compare both the sums
8 < 9
Therefore , 9 is greater than 8

Question 7.
YOU BE THE TEACHER
Circle to show who is correct. Show how you know.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 46
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Subtract-1-Practice-2.3-Question-7
Explanation:
when a number is reduced by 1, then we get the previous number of that number as difference.
previous number of 6 is 5 .
Therefore difference = 5

Question 8.
Modeling Real Life
You have 3 karate belts. Newton has I fewer than you. Descartes has I more than you. Who has fewer, Newton or Descartes?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 47
Who has fewer?           Newton          Descartes
Answer:
Number of karate belts = 3
Number of belts with Newton = 3 – 1 = 2
Number of belts with Descartes = 3 + 1 = 4
Newton have 2 fewer belts than Descartes.

Review & Refresh

Question 9.
Use the picture to complete the number bond.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 48
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Subtract-1-Practice-2.3-Question-9

Lesson 2.4 Add Doubles from 1 to 5

Explore and Grow

Use counters to model the story.

You have 3 balls. Your friend has 3 balls. How many balls are there in all?
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 49
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Explore-Grow
Explanation:
Here we have 2 groups . each group contains 3 balls.
So total number of groups = 2
Total number of balls  = 3 + 3 = 6

Show and Grow

Question 1.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 50
___________ – ___________ = ___________
Answer:
4 – 4 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 51
___________ + ___________ = ___________
Answer:
1 + 1 = 2
Explanation:
when a given number is increased by 1 then we get the next number of that number, Also, we know that a next number of a number is called successor.
The next number of 1 is 2.

Question 3.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 52
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Show-Grow-Question-3
Explanation:
From the above figure we notice 4 are addends .Now add both the numbers
4 + 4 = 8
Therefore the sum is 8.

Question 4.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 53
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Show-Grow-Question-4
Explanation:
From the above figure we notice 3 are addends .Now add both the numbers
3 + 3 = 6
Therefore the sum is 6.

Apply and grow: Practice

Question 5.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 54
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Apply-Grow-Practice-Question-5
Explanation:
From the above figure we notice 5 are addends .Now add both the numbers
5 + 5 = 10
Therefore the sum is 10.

Question 6.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 55
Answer:
2 + 2 = 4
2 – 2 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 7.
2 + 2 = ______
Answer:
2 + 2 = 4
Explanation:
From the above figure we notice 2 are addends .Now add both the numbers
2 + 2 = 4
Therefore the sum is 4.

Question 8.
5 + 5 = _______
Answer:
5 + 5 = 10
Explanation:
From the above figure we notice 5 are addends .Now add both the numbers
5 + 5 = 10
Therefore the sum is 10.

Question 9.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 56
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Apply-Grow-Practice-Question-9
Explanation:
From the above figure we notice 3 are addends .Now add both the numbers
3 + 3 = 6
Therefore the sum is 6.

Question 10.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 57
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Apply-Grow-Practice-Question-10
Explanation:
From the above figure we notice 4 are addends .Now add both the numbers
4 + 4 = 8
Therefore the sum is 8.

Question 11.
DIG DEEPER!
Circle the equations you can complete using doubles.
________ + ________ =               6 ________ + ________ = 5

________ + ________ =               9 ________ + ________ = 2
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Apply-Grow-Practice-Question-11

Think and Grow: Modeling Real Life

You and your friend color the same number of pictures. There are to pictures in all. How many pictures do you each color?
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 58
Draw a Picture:

Addition equation:

__________ pictures

Show and Grow

Question 12.
You and your friend have the same number of flowers. There are 8 flowers in all. How many flowers do you each have?
Draw a picture:

Addition equation:

________ flowers
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson 2.4 -Add-Doubles-from-1 to 5-Show-Grow-Question-12
Number of flowers with me = x
Number of flowers with my friend = x
Total number of flowers = 8
x + x = 8
4 + 4 = 8.

Add Doubles from 1 to 5 Practice 2.4

Question 1.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 59
___________ + ___________ = ___________
Answer:
4 + 4 = 8

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 60
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Doubles-from-1 to 5-Practice-2.4-Question-2

Explanation:
From the above figure we notice 3 are addends .Now add both the numbers
3 + 3 = 6
Therefore the sum is 6.

Question 3.
2 + 2 = ________
Answer:
2 + 2 = 4
Explanation:
From the above figure we notice 2 are addends .Now add both the numbers
2 + 2 = 4
Therefore the sum is 4.

Question 4.
4 + 4 = _________
Answer:
4 + 4 = 8
Explanation:
From the above figure we notice 4 are addends .Now add both the numbers
4 + 4 = 8
Therefore the sum is 8.

Question 5.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 61
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Doubles-from-1 to 5-Practice-2.4-Question-5
Explanation:
From the above figure we notice 5 are addends .Now add both the numbers
5 + 5 = 10
Therefore the sum is 10.

Question 6.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 62
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Doubles-from-1 to 5-Practice-2.4-Question-6
Explanation:
From the above figure we notice 3 are addends .Now add both the numbers
3 + 3 = 6
Therefore the sum is 6.

Question 7.
DIG DEEPER!
Circle the equations you can complete using doubles.
_________ + _________ = 3            _________ + _________= 8

_________ + _________ = 4            _________ + _________ = 7
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Add-Doubles-from-1 to 5-Practice-2.4-Question-7

Question 8.
Modeling Real Life
Newton and Descartes each have the same number of linking cubes. There are 6 linking cubes in all. How many linking cubes do Newton and Descartes have?
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 63

 

________ linking cubes
Answer:
Total Number of linking cubes = 6.
Newton and Descartes each have the same number of linking cubes
Each have 3 linking cubes
3 + 3 = 6.
Newton and Descartes each have 3 linking cubes.

Review & Refresh

Use the picture to write an equation.

Question 9.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 64
___________ + ___________ = ___________
Answer:
2 + 3 = 5
Explanation:
we notice 2 hippos in the mud and 3 hippos came to join them.
so total number of hippos are add 2 and 3
Total number of hippos = 2 + 3 = 5

Question 10.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 65
___________ + ___________ = ___________
Answer:
4 + 5 = 9
Explanation:
We notice 4 zebras eating grass and 5 zebras joining them
so total number of zebras are add 4 and 5
Total number of zebras = 4 + 5 = 9

Lesson 2.5 Use Doubles

Explore and Grow

Use counters to model the story.

You collect 4 shells. Your friend collects 4 shells. How many shells are there in all?

____ shells

Answer:
Number of shells with me = 4
Number of shells with my friend= 4
Total Number of shells = 4 + 4 = 8

You collect 4 shells. Your friend collects 5 shells. How many shells are there in all?

 

____ shells
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 66
Answer:
Number of shells with me = 4
Number of shells with my friend= 5
Total Number of shells = 4 + 5 = 9

Show and Grow

Use the double 3 + 3 to find each sum.

Question 1.
3 + 4 = ______
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 67
Answer:
3 + 3 + 1 = 7

Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 68
Answer:
3 + 3 – 1 = 5

Apply and Grow: Practice

Use the double 2 + 2 to find each sum.

Question 2.
2 + 3 = ______
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 69
Answer:
2 + 2 + 1 =5

2 + 1 = ______
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 70
Answer:
2 + 2 – 1 = 3

Find the sum. Write the double you used.

Question 3.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 71
Answer:
3 + 4 = 7
3 + 3 + 1 = 6 + 1 = 7

Question 4.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 72
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Lesson-2.5-Use-Doubles-Question-4

Question 5.
MP Number Sense
Use each card once to write two addition equations.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 73
Answer:
2 + 2 = 4
2 + 3 = 5

Think and Grow: Modeling Real Life

You eat 4 grapes. Your friend eats I more than you. How many grapes do you and your friend eat in all?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 74
Which doubles can you use to find the sum?
4 + 4              5 + 5                3 + 3
Addition equation:

__________ grapes
Answer:
Number of grapes ate by me = 4
Number of grapes ate by my friend = 4 + 1
Number of grapes eaten = 4 + 4 + 1 = 9
4 + 4 is used to find the sum

Show and Grow

Question 6.
You have 5 toy cars. Your friend has I fewer than you. How many cars do you and your friend have in all?

Which doubles can you use to find the sum?
4 + 4            6 + 6              5 + 5
Addition equation:

 

_________ toy cars
Answer:
Number of toy cars with me = 5
Number of toy cars with my friend = 5 – 1
Total Number of cars = 5 + 5 – 1 = 10 – 1 = 9

Use Doubles Practice 2.5

Use the double 4 + 4 to find each sum.

Question 1.
4 + 5 = _______
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 75
Answer:
4 + 4 + 1 = 8 + 1 = 9

4 + 3 = _______
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 76
Answer:
4 + 4 – 1 = 8 – 1 = 7

Find the sum. Write the double you used.

Question 2.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 77
Answer:
1 + 1 = 2
1 + 2 = 3

Question 3.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 78
Answer:
1 + 1 = 2
3 + 2 = 5

Question 4.
Number Sense
Use each card once to write two addition equations.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 79
Answer:
2 + 3 = 5
3 + 3 = 6

Question 5.
Modeling Real Life
Newton catches 2 butterflies. Descartes catches I more than Newton. How many butterflies do Newton and Descartes catch in all?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 80
Which doubles can you use to find the sum?
3 + 3              1 + 1              2 + 2

 

_________ butterflies
Answer:
Number of butterflies with Newton = 2
Number of butterflies with Descartes = 2 + 1.
Total number of butterflies both caught = 2 + 2 + 1 = 4 + 1 = 5

Review & Refresh

Question 6.
Circle the model that shows the missing number.
2 + ______ = 5
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 81
Answer:
2 + 3 = 5
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Lesson-2.5-Use-Doubles-Question-6

Lesson 2.6 Add in Any Order

Explore and Grow

Use counters to model each problem. What do you notice?

4 + 3 = ____7_____

3 + 4 = ___7______

Show and Grow

Question 1.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 82
_________ + _________ = _________
Answer:
2 + 4 = 6
Explanation:
From the above figure we notice 2 and 4 are addends .Now add both the numbers
2 + 4 = 6
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 6

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 83
_________ + _________ = _________
Answer:
4 + 2 = 6
Explanation:
From the above figure we notice 2 and 4 are addends .Now add both the numbers
2 + 4 = 6

Question 2.Whatever may be the order of addends the sum is always the same.
Therefore the sum is 6
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 84
_________ + _________ = _________
Answer:
7 + 1 = 8
Explanation:
when a given number is increased by 1 then we get the next number of that number as sum.
The next number of 7 is 8 as sum.
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 8

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 85
_________ + _________ = _________
Answer:
1 + 7 = 8
Explanation:
when a given number is increased by 1 then we get the next number of that number as sum.
The next number of 7 is 8 as sum.
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 8

Question 3.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 86
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Lesson-2.6-Add-Any-Order- Show and Grow-Question-3

2 + 3 = 5
Explanation:
From the above figure we notice 2 and 3 are addends .Now add both the numbers
2 + 3 = 5
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 5

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 87
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Lesson-2.6-Add-Any-Order- Show and Grow-Question-3.

Explanation:
From the above figure we notice 2 and 3 are addends .Now add both the numbers
3 + 2 = 5
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 5

Apply and Grow: Practice

Question 4.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 88
_________ + _________ = _________
Answer:
7 + 3 = 10
Explanation:
From the above figure we notice 7 and 3 are addends .Now add both the numbers
7 + 3 = 10
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 10

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 89
_________ + _________ = _________
Answer:
3 + 7 = 10
Explanation:
From the above figure we notice 3 and 7 are addends .Now add both the numbers
3 + 7 = 10
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 10

Find the sum. Then change the order of the addends. Write the new addition problem.

Question 5.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 90
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Lesson-2.6-Add-Any-Order- Show and Grow-Question-5
Explanation:
From the above figure we notice 1 and 4 are addends .Now add both the numbers
1 + 4 = 5 or 4 + 1 = 5
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 5

Question 6.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 91
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Lesson-2.6-Add-Any-Order- Show and Grow-Question-6

Explanation:
From the above figure we notice 5 and 2 are addends .Now add both the numbers
5 + 2 = 7 or 2 + 5 = 7
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 7

Question 7.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 92
Answer:
2 + 6 = 8
6 + 2 = 8
Explanation:
From the above figure we notice 6 and 2 are addends .Now add both the numbers
6 + 2 = 8 or 2 + 6 = 8
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 8

Question 8.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 93
Answer:
9 = 8 + 1
9 = 1 + 8
Explanation:
From the above figure we notice 8 and 1 are addends .Now add both the numbers
8 + 1 = 9 or 1 + 8 = 9
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 9

Question 9.
MP Number Sense
Use the numbers shown to write two addition equations.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 94
Answer:
4 + 5 = 9
5 + 4 = 9
Explanation:
From the above figure we notice 4 and 5 are addends .Now add both the numbers
4 + 5 = 9 or 5 + 4 = 9
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 9

Think and Grow: Modeling Real Life

You have 7 shirts. 3 are green. The rest are blue. How many blue shirts do you have?
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 95
Which equations describe your shirts?
3 + 4 = 7            3 + 7 = 10
7 + 3 = 10          4 + 3 = 7
Show how you know:

You have ____ blue shirts.
Answer:
Number of green shirts = 3
Number of blue shirts  =  X
Total number of shirts = 7
3 + X = 7
X = 7 – 3 = 4
Number of blue shirts = 4
Equation: 3 + 4 = 7 or 4 + 3 = 7

Show and Grow

Question 10.
You have 5 cups. 2 are yellow. The rest are red. How many red cups do you have?
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 96
Which equations describe your cups?
5 + 2 = 7               2 + 3 = 5
2 + 5 = 7               3 + 2 = 5
Show how you know:

You have ____ red cups.
Answer:
Number of red cups = x
Number of yellow cups = 2
Total number of cups = 5
x + 2 = 5
x = 5 – 2 = 3
Number of red cups = 3
Equation : 3 + 2 = 5 or 2 + 3 = 5

Add in Any Order Practice 2.6

Question 1.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 97

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 98
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Add-in-Any-Order-Practice-2.6-Question-1
Explanation:
From the above figure we notice 3 and 4 are addends .Now add both the numbers
3 + 4 = 7 or 4 + 3 = 7
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 7

Question 2.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 99
Answer:
7 + 2 = 9

Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 100
Answer:
2 + 7 = 9
Explanation:
From the above figure we notice 2 and 7 are addends .Now add both the numbers
2 + 7= 9 or 7 + 2 = 9
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 9

Find the sum. Then change the order of the addends. Write the new addition problem.

Question 3.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 101
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10- Add-in-Any-Order-Practice-2.6-Question-3
Explanation:
From the above figure we notice 6 and 4 are addends .Now add both the numbers
6 + 4 = 10 or 4 + 6 = 10
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 10

Question 4.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 102
Answer:
6 = 5 + 1
6 = 1 + 5
Explanation:
From the above figure we notice 6 and 4 are addends .Now add both the numbers
5 + 1 = 6 or 1 + 5 = 6
when a given number is increased by 1 then we get the next number of that number as sum
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 6

Question 5.
MP Number Sense
Use the numbers shown to write two addition equations.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 103
Answer:
2 + 8 = 10
8 + 2 = 10
Explanation:
From the above equations we notice 2 and 8 are addends .Now add both the numbers
2 + 8 = 10 or 8 + 2 = 10
Whatever may be the order of addends the sum is always the same.
Therefore the sum is 10

Question 6.
Modeling Real Life
You have 7 tomatoes. 2 are red. The rest are yellow. How many yellow tomatoes do you have?
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 104
Which equations describe your tomatoes?
2 + 5 = 7 5 + 2 = 7
7 + 2 = 9 2 + 7 = 9
Show how you know:

You have _______ yellow tomatoes.
Answer:
Total number of tomatoes = 7
Number of red tomatoes = 2
Number of yellow tomatoes = x
Explanation:
7 = 2 + x
x = 7 – 2 = 5
Number of yellow tomatoes = 5
Equations: 2 + 5 = 7 or 5 + 2 = 7

Review & Refresh

Use the ten frame to complete the equation.

Question 7.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 105
5 + _______ = 8
Answer:
5 + 3 = 8
Explanation:
From the above equation we notice to get 8 as sum what should be added for 5
if we add 3 to 5 we get 8 as sum.
Therefore 5 + 3 = 8 .

Question 8.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 106
5 + ________ = 10
Answer:
5 + 5 = 10
Explanation:
From the above equation we notice to get 10 as sum what should be added for 5
if we add 5 to 5 we get 10 as sum.
Therefore 5 + 5 = 10 .

Lesson 2.7 Count on to Add

Explore and Grow

Model the story.

There are 5 coins in a piggy bank. You put in 2 more. How many coins are in the bank now?

Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 107
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.7-Count-on-to-Add-Explore-Grow
Number of coins in piggy bank = 5
Number of coins added = 2
Total coins = 5 + 2 = 7.

Show and Grow

Question 1.
7 + 2 = _________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 108
Answer:
7 + 2 = 9
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.7-Count-on-to-Add-Show-Grow-Question-1
Explanation:
Count on method to add numbers. To add 7 and 2, start from 7 and count on 2 steps to arrive at the sum (9).

Question 2.
3 + 1 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 109
Answer:
3 + 1 = 4
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.7-Count-on-to-Add-Show-Grow-Question-2
Explanation:
Count on method to add numbers. To add 3 and 1, start from 3 and count on 1 step to arrive at the sum (4).

Question 3.
4 + 6 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 110
Answer:
4 + 6 = 10
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-Strategies-within-10-Lesson-2.7-Count-on-to-Add-Show-Grow-Question-3
Explanation:
Count on method to add numbers. To add 4 and 6, start from 4 and count on 6 steps to arrive at the sum (10).

Question 4.
0 + 5 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 111
Answer:
0 + 5 = 5
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Show-Grow-Question-4

Explanation:
Count on method to add numbers. To add 0 and 5, start from 0 and count on 5 steps to arrive at the sum (5).

Apply and Grow: practice

Question 5.
4 + 2 = _________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 112
Answer:
4 + 2 = 6
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Apply-Grow-practice-Question-5
Explanation:
Count on method to add numbers. To add 4 and 2, start from 4 and count on 2 steps to arrive at the sum (6).

Question 6.
6 + 1 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 112
Answer:
6 + 1 = 7

Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Apply-Grow-practice-Question-6
Explanation:
Count on method to add numbers. To add 6 and 1, start from 6 and count on 1 step to arrive at the sum (7).

Question 7.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 113
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Apply-Grow-practice-Question-7
Explanation:
From the above figure we notice 5 and 4 are addends .Now add both the numbers
5 + 4 = 9
Therefore the sum is 9.

Question 8.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 114
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Apply-Grow-practice-Question-8
Explanation:
From the above figure we notice 3 and 2 are addends .Now add both the numbers
3 + 2 = 5
Therefore the sum is 5.

Question 9.
________ = 0 + 7
Answer:
7 = 0 + 7
Explanation:
From the above figure we notice 0 and 7 are addends . Adding 0 to any number gives the sum as the number itself.Now add both the numbers
0 + 7 = 7
Thus the result is 7.

Question 10.
________ = 2 + 8
Answer:
10 = 2 + 8
Explanation:
From the above figure we notice 8 and 2 are addends .Now add both the numbers
2 + 8 = 10
Therefore the sum is 10.

Question 11.
DIG DEEPER!
Tell what problems Newton and Descartes solved. Think: How are the problems the same? How are they different?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 115
Answer:

Think and Grow: Modeling Real Life

You and your friend are on a scavenger hunt. You find 3 clues. You and your friend find 8 clues in all. How many clues does your friend find?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 116
Model:

Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 117

______ clues
Answer:
Number of clues with me = 3
Number of clues with my friend = x
Total number of clues = 8
Explanation:
3 + x = 8
x = 8 – 3 = 5
Number of clues with my friend = 5
Equation: 3 + 5 = 8
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Think-Grow-Modeling-Real-Life
Explanation:
Count on method to add numbers. To add 3 and 5 start from 3 and count on 5 steps to arrive at the sum (8).

Show and Grow

Question 12.
Your friend collects 4 cans. You and your friend collect 10 cans in all. How many cans do you collect?
Model:

Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 117

________ cans
Answer:
Number of cans with my friend = 4
Total number of cans = 10
Number of cans with me  = X
Explanation:
4 + X = 10
X= 10 – 4 = 6
Number of cans with me = 6
Equation: 4 + 6 = 10
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.7-Count-on-to-Add-Show-Grow- Question-12
Explanation:
Count on method to add numbers. To add 4 and 6, start from 4 and count on 6 steps to arrive at the sum (10).

Count on to Add Practice 2.7

Question 1.
4 + 3 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 118
Answer:
4 + 3 = 7
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-1
Explanation:
Count on method to add numbers. To add 4 and 3 start from 3 and count on 3 steps to arrive at the sum (7).

Question 2.
8 + 1 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 118
Answer:
8 + 1 = 9
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-2
Explanation:
Count on method to add numbers. To add 8 and 1 start from 8 and count on 1 step to arrive at the sum (9).

Question 3.
6 + 2 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 118
Answer:
6 + 2 = 8
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-3
Explanation:
Count on method to add numbers. To add 6 and 2 start from 6 and count on 2 steps to arrive at the sum (8).

Question 4.
7 + 3 = ________
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 118
Answer:
7 + 3 = 10
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-4
Explanation:
Count on method to add numbers. To add 7 and 3 start from 7 and count on 3 steps to arrive at the sum (10).

Question 5.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 119
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-5

Explanation:
From the above figure we notice 0 and 9 are addends . Adding 0 to any number gives the sum as the number itself.Now add both the numbers
0 + 9 = 9
Thus the result is 9.

Question 6.
______ = 1 + 5
Answer:
6 = 1 + 5
Explanation:
when a given number is increased by 1 then we get the next number of that number as sum.
The next number of 5 is 6
Therefore sum = 6 .

Question 7.
DIG DEEPER!
Tell what problems Newton and Descartes solved. Think: How are the problems the same? How are they different?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 120Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 120
Answer:
Both the problems are the same .
sum is the same only the order of the addends are different .
Newton have 3 and 4 as addends 3 added to 4 whereas in Descartes the 4 is added to 3. whatever may be the order of addends the sum will always be the same .
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-7

Question 8.
Modeling Real Life
You have 4 coins. You and your friend have 9 coins in all. How many coins does your friend have?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 121
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 118

 

__________ coins
Answer:
Number of coins with me = 4
Number of coins with my friend = X
Total coins = 9
Explanation:
4 + X = 9
X = 9 -4 = 5
Number of coins with my friend = 5
Equation : 4 + 5 = 9
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Count-on-to-Add-Practice-2.7-Question-8
Explanation:
Count on method to add numbers. To add 4 and 5 start from 4 and count on 5 steps to arrive at the sum (9).

Review & Refresh

Use the picture to write an equation.

Question 9.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 122
Answer:
4 – 1 = 3
Explanation:
when a number is reduced by 1, then we get the previous number of that number as difference.
previous number of 4 is 3 .
Therefore difference = 3

Question 10.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 123
Answer:
5 – 3 = 2
Explanation:
From the above equation we notice 5 is minuend and 3 is subtrahend.
Now subtract
5 – 3 = 2
Thus the difference is 2

Lesson 2.8 Count Back to Subtract

Explore and Grow

Model the story.

There are 8 students in a line. 2 of them leave. How many students are left?
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 124
Answer:
Number of students = 8
Number of students left = 2
Number of students remained in class = 8 – 2 = 6
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Explore-Grow

Show and Grow

Question 1.
5 – 4 = _________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 125
Answer:
5 – 4 = 1
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Show-Grow-Question-1
Explanation:
Use the count back method to subtract.To subtract 4 from 5, one can start at 5 and count back 4 steps we get difference as 1.

Question 2.
7 – 3 = ________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 126
Answer:
7 – 3 = 4
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Show-Grow-Question-2
Explanation:
Use the count back method to subtract.To subtract 3 from 7, one can start at 7 and count back 3 steps we get difference as 4.

Question 3.
6 – 1 = _________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 127
Answer:
6 – 1 = 5
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Show-Grow-Question-3
Explanation:
Use the count back method to subtract.To subtract 1 from 6, one can start at 6 and count back 1 step we get difference as 5.

Question 4.
10 – 8 = ________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 127
Answer:
10 – 8 = 2
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Show-Grow-Question-4
Explanation:
Use the count back method to subtract.To subtract 8 from 10, one can start at 10 and count back 8 steps we get difference as 2.

Apply and Grow: Practice

Question 5.
10 – 6 = _________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 127
Answer:
10 – 6 = 4
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Apply-Grow-Practice-Question-5
Explanation:
Use the count back method to subtract.To subtract 6 from 10, one can start at 10 and count back 6 steps we get difference as 4.

Question 6.
9 – 3 = _________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 127
Answer:
9 – 3 = 6
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Apply-Grow-Practice-Question-6
Explanation:
Use the count back method to subtract.To subtract 3 from 9, one can start at 9 and count back 3 steps we get difference as 6.

Question 7.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 128
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Apply-Grow-Practice-Question-7
Explanation:
From the above equation we notice 5 is minuend and 2 is subtrahends. Now subtract the 5 and 2
5 – 2 = 3
Thus the difference is 3

Question 8.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 129
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Apply-Grow-Practice-Question-8

Explanation:
From the above equation we notice 8 is minuend and 0 is subtrahends Subtracting 0 from any number gives the number itself as the difference. Now subtract the 8 and 0
8 – 0 = 8
Thus the difference is 8

Question 9.
________ = 7 – 6
Answer:
1

Question 10.
_________ = 4 – 1
Answer:
3

Question 11.
MP Structure
Write the problem shown.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 130
_________ – _________ = ________
Answer:
9 – 5 = 4
Explanation:
Use the count back method to subtract.To subtract 5 from 9, one can start at 9 and count back 5 steps we get difference as 4.

Think and Grow: Modeling Real Life

There are 5 students on one side of a table and 5 students on the other. 7 students leave. How many students are left?
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 131
Model:
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 132

__________ students
Answer:
Total Number of students = 5 + 5 = 10
Number of students left = 7
Remaining Number of students = 10 – 7 = 3
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Think- Grow-Modeling-Real-Life
Explanation:
Use the count back method to subtract.To subtract 7 from 10, one can start at 10 and count back 7 steps we get difference as 3

Show and Grow

Question 12.
You have 4 board games and 4 card games. You give 3 games to your friend. How many games do you have left?
Model:
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 132

 

__________ games
Answer:
Total Number of games  = 4 + 4 = 8
Number of games given to my friend = 3
Remaining Number of games with me =8 – 3 = 5
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson-2.8-Count-Back-to-Subtract-Show-Grow-Question-12
Explanation:
Use the count back method to subtract.To subtract 3 from 8, one can start at 8 and count back 3 steps we get difference as 5

Count Back to Subtract Practice 2.8

Question 1.
5 – 4 = ________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 133
Answer:
5 – 4 = 1
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Practice-2.8-Question-1
Explanation:
Use the count back method to subtract.To subtract 4 from 5, one can start at 5 and count back 4 steps we get difference as 1

Question 2.
8 – 3 = ________
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 133
Answer:
8 – 3 = 5
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Practice-2.8-Question-2
Explanation:
Use the count back method to subtract.To subtract 3 from 8, one can start at 8 and count back 3 steps we get difference as 5

Question 3.
9 – 1 = ________
Answer:
9 – 1 = 8
Explanation:
when a number is reduced by 1, then we get the previous number of that number as difference.
previous number of 9 is 8 .
Therefore difference = 8

Question 4.
6 – 2 = ________
Answer:
6 – 2 = 4
Explanation:
From the above equation we notice 6 is minuend and 2 is subtrahend.
Now subtract
6 – 2 = 4
Thus the difference is 4

Question 5.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 134
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Practice-2.8-Question-5
Explanation:
From the above equation we notice 7 is minuend and 5 is subtrahend.
Now subtract
7 – 5 = 2
Thus the difference is 2

Question 6.
__________ = 10 – 5
Answer:
5
Explanation:
From the above equation we notice 10 is minuend and 5 is subtrahend.
Now subtract
10 – 5 = 5
Thus the difference is 5

Question 7.
MP Structure
Write the problem shown.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 135
__________ – _________ = _________
Answer:
9 – 7= 2
Explanation:
Use the count back method to subtract.To subtract 7 from 9, one can start at 9 and count back 7 steps we get difference as 2

Question 8.
Modeling Real Life
You have 4 star stickers and 4 heart stickers. You give 6 away. How many stickers do you have left?
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 136

 

__________ stickers
Answers:
Total Number of stickers = 4 + 4 = 8
Number of stickers given away = 6
Remaining number of stickers = 8 – 6 = 2
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Practice-2.8-Question-8
Explanation:
Use the count back method to subtract.To subtract 6 from 8, one can start at 8 and count back 6 steps we get difference as 2

Review & Refresh

Question 9.
Use the pictures to write the related equations.
Big Ideas Math Answer Key Grade 1 Chapter 2 Fluency and Strategies within 10 137
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Practice-2.8-Question-9

Lesson 2.9 Use Addition to Subtract

Explore and Grow

Use counters to model each problem.

 

4 + ___3___ = 7

 

7 – 4 = __3___

Show and Grow

Question 1.
5 – 4 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 138
Think 4 + ______ = 5
So, 5 – 4 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Show-Grow-Question-1
Think 4 + 1 = 5
So, 5 – 4 = 1 .

Question 2.
6 – 3 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 139
Think 3 + ______ = 6
So, 6 – 3 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Show-Grow-Question-2
Think 3 + 3 = 6
So, 6 – 3 = 3 .

Apply and Grow: Practice

Question 3.
8 – 4 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 140
Think 4 + ______ = 8.
So, 8 – 4 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Apply-Grow-Practice-Question-3
Think 4 + 4 = 8.
So, 8 – 4 = 4 .

Question 4.
7 – 5 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 141
Think 5 + ______ = 7.
So, 7 – 5 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Apply-Grow-Practice-Question-4
Think 5 + 2 = 7.
So, 7 – 5 = 2 .

Question 5.
6 – 4 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 142
Think ______ + ______ = 6.
So, 6 – 4 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Apply-Grow-Practice-Question-5
Think 2+ 4 = 6.
So, 6 – 4 = 2 .

Question 6.
9 – 6 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 143
Think ______ + ______ = 9.
So, 9 – 6 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Apply-Grow-Practice-Question-6
Think 3 + 6 = 9.
So, 9 – 6 =  3 .

Question 7.
YOU BE THE TEACHER
There are 8 goats. 2 of them leave. Newton uses addition to tell how many goats are left. Is he correct? Show how you know.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 144
Answer:
No, we have to subtract when goats leaves not addition.
8 – 2 = 6

Think and Grow: Modeling Real life

There are 10 puppies. 7 are brown. The rest are yellow. How many puppies are yellow?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 145
Model:
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 146
Subtraction equation:

_________ puppies
Answer:
Total number of puppies = 10
Number of brown puppies = 3
Number of yellow puppies = 10 – 3 = 7
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Think-Grow-Modeling-Real-life

Show and Grow

Question 8.
There are 8 eggs. I of them hatches. How many eggs still need to hatch?
Model:
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 147
Subtraction equation:

__________ eggs
Answer:
Total number of eggs = 8
Number of eggs hatched = 1.
Numbers of eggs left for hatching = 8 – 1 = 7
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Lesson 2.9-Use-Addition-to-Subtract-Show-Grow-Question-8

Use Addition to Subtract Practice 2.9

Question 1.
3 – 2 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 148
Think 2 + ______ = 3.
So, 3 – 2 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Practice-2.9-Question-1
Think 2 + 1 = 3.
So, 3 – 2 = 1

Question 2.
10 – 5 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 149
Think 5 + ______ = 10.
So, 10 – 5 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Practice-2.9-Question-2
Think 5 + 5 = 10.
So, 10 – 5 = 5

Question 3.
9 – 5 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 150
Think ______ + ______ = ______.
So, 9 – 5 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Practice-2.9-Question-3
Think 4 + 5 = 9.
So, 9 – 5 = 4

Question 4.
7 – 6 = ?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 151
Think ______ + ______ = ______.
So, 7 – 6 = _______ .
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Practice-2.9-Question-4
Think 1 + 6 = 7.
So, 7 – 6 = 1

Question 5.
YOU BE THE TEACHER
There are 8 birds. 5 fly away. Descartes uses addition to tell how many birds are left. Is he correct? Show how you know.
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 152
Answer:
Numbers of birds = 8
Number of birds flew = 5
Remaining number of birds = 8 – 5 = 3
Descartes is wrong we need to subtract not addition .

Question 6.
Modeling Real Life There are 9 kittens. 7 are adopted. How many kittens still need to be adopted?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 153

_______ kittens
Answer:
Total Number of kittens = 9
Number of kittens  adopted = 7
Number of kittens remaining for adoption = 9 – 7 = 2
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Practice-2.9-Question-6

Review & Refresh

Question 7.
You have 5 Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 154 and 2 Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 155 How many dice do you have in all?
Big Ideas Math Answers 1st Grade 1 Chapter 2 Fluency and Strategies within 10 156
_________ + _________ = ________ dice
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Practice-2.9-Question-7
5 + 2 = 7
Number of red dices = 5
Number of blue dices = 2
Total dices = 5 + 2 = 7

Fluency and Strategies within 10 Performance Task

Question 1.
You plant 4 red flower seeds and 4 yellow flower seeds. Your friend plants 5 red flower seeds and 4 yellow flower seeds.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 157

a. I of your yellow seeds does not grow. How many of your flowers grow?

_________ flowers
Answer:
Total number flower seeds = 4 + 4 = 8
Number of yellow seeds didn’t grow = 1
Number of your flowers grown = 8 – 1 = 7

b. 3 of your friend’s red seeds do not grow. How many of your friend’s flowers grow?

________ flowers
Answer:
Total number of my friends flowers = 5 + 4 = 9 (red and yellow )
Number of red seeds didn’t grow of my friend’s = 3
Number of your flowers grown of my friend’s= 9 – 3 = 6

c. Who has more flowers?

You       Friend

Answer: I have more flowers

d. How many more red flowers do you have than your friend?

_______ flowers
Answer:
I have 4 red flowers
My friend 2 red flowers (5 – 3 )

Fluency and Strategies within 10 Chapter Practice

Add 0 Homework & Practice 2.1

Use the picture to write an equation.

Question 1.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 158
_______ + 0 = ________
Answer:
2 + 0 = 2
Explanation:
From the above figure we notice 2 and 0 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
2 + 0 = 0
Thus the result is 2.

Question 2.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 159
0 + _______ = ________
Answer:
0 + 5 = 5
Explanation:
From the above figure we notice 5 and 0 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
5 + 0 = 0
Thus the result is 5.

Question 3.
7 + 0 = ________
Answer:
7 + 0 = 7
Explanation:
From the above figure we notice 7 and 0 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
7 + 0 = 0
Thus the result is 7.

Question 4.
0 + 6 = ________
Answer:
0 + 6 = 6
Explanation:
From the above figure we notice 6 and 0 are addends . Adding 0 to any number gives the sum as the number itself. Now add both the numbers
6 + 0 = 0
Thus the result is 6.

Subtract 0 and Subtract All Homework & Practice 2.2

Use the picture to write an equation.

Question 5.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 160
________ – 0 = ________
Answer:
7 – 0 = 7
Explanation:
From the above equation we notice 7 is minuend and 0 is subtrahends Subtracting 0 from any number gives the number itself as the difference. Now subtract the 7 and 0
7 – 0 = 7
Thus the difference is 7

Question 6.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 161
_________ – ________ = 0
Answer:
7 – 7 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 7.
9 – 9 = ______
Answer:
9 – 9 = 0
Explanation:
When a number is subtracted from itself the difference is always equal to 0.
Thus the difference is 0

Question 8.
8 – 0 = _______
Answer:
8 – 0 = 8
Explanation:
From the above equation we notice 8 is minuend and 0 is subtrahends Subtracting 0 from any number gives the number itself as the difference. Now subtract the 8 and 0
8 – 0 = 8
Thus the difference is 8

Add and Subtract I Homework & Practice 2.3

Use the picture to write an equation.

Question 9.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 162
________ + ________ = _________
Answer:
8 + 1 = 9
Explanation:
As per the above picture , we can notice 8 people are playing and 1 more person joining them
So total number of people are 8 + 1 = 9
Total number of people = 9

Question 10.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 163
________ – ________ = _________
Answer:
8 – 1 = 7
Explanation:
As per the above picture , we can notice 7 people are playing and 1 person leaving them
So total number of people are 7 – 1 = 6
Total number of people = 6

Question 11.
3 – 1 = ________
Answer:
3 – 1 = 2
Explanation:
when a number is reduced by 1, then we get the previous number of that number as difference.
previous number of 3 is 2 .
Therefore difference = 2

Question 12.
5 + 1 = ________
Answer:
5 + 1 = 6
Explanation:
when a given number is increased by 1 then we get the next number of that number as sum
Therefore the sum is 6

Add Doubles from 1 to 5 Homework & Practice 2.4

Question 13.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 164
Answer:
2 + 2 = 4

Question 14.
Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 165Big Ideas Math Answers Grade 1 Chapter 2 Fluency and Strategies within 10 162
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Add-Doubles-from-1 to 5-Homework-Practice-2.4-Question-14
8 + 1 = 9

Question 15.
MP Reasoning
Circle the equations you can complete using doubles.
_________ + ________ = 10 _________ + ________ = 3

_________ + ________ = 6 _________ + ________ = 7
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Add-Doubles-from-1 to 5-Homework-Practice-2.4-Question-15

Use Doubles Homework & Practice 2.5

Use the doubles 2 + 2 to find each sum.

Question 16.
2 + 3 = _______

Answer:
2 + 3 = 5
2 + 2 + 1 = 5

2 + 1 = _______

Answer:
2 + 1 =3
2 + 2 – 1 = 3

Find the sum. Write the double you used.

Question 17.

Answer:
4 + 5 = 9
5 + 4 = 9

Question 18.

Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10- Use-Doubles-Homework-Practice-2.5-Question-18

Add in any Order Homework & Practice 2.6

Question 19.

_______ + ______ = ______
Answer:
5 + 2 = 7


_______ + ______ = ______
Answer:
2 + 5 = 7

Question 20.
MP Number Sense
Use the numbers shown to write two addition equations.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 172
Answer:
3 + 6 = 9
6 + 3 = 9

Count on to Add Homework & Practice 2.7

Question 21.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 173
5 + 2 = _________
Answer:
5 + 2 = 7
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-addition-Homework-Practice-2.8-Question-21

Explanation:
Count on method to add numbers. To add 5 and 2, start from 5 and count on 2 steps to arrive at the sum (7).

Question 22.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 173
6 + 4 = __________
Answer:
6 + 4 = 10
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-addition-Homework-Practice-2.8-Question-22

Explanation:
Count on method to add numbers. To add 6 and 4, start from 6 and count on 4 steps to arrive at the sum (10).

Count Back to Subtract Homework & Practice 2.8

Question 23.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 173
9 – 7 = __________
Answer:
9 – 7 = 2
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Homework-Practice-2.8-Question-23

Explanation:
Use the count back method to subtract.To subtract 7 from 9, one can start at 9 and count back 7 steps we get difference as 2

Question 24.
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 173
10 – 5 = _________
Answer:
10 – 5 = 5
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Count-Back-to-Subtract-Homework-Practice-2.8-Question-24
Explanation:
Use the count back method to subtract.To subtract 10 from 5, one can start at 10 and count back 5 steps we get difference as 5

Use Addition to Subtract Homework & Practice 2.9

Question 25.
5 – 3 = ?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 174
Think 3 + ______ = 5.
So, 5 – 3 = ______.
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Homework-Practice-2.9-Question-25
Think 3 + 2 = 5.
So, 5 – 3 = 2

Question 26.
9 – 8 =?
Big Ideas Math Solutions Grade 1 Chapter 2 Fluency and Strategies within 10 175
Think 8 + ______ = 9.
So, 9 – 8 = ______.
Answer:
Big-Ideas-Math-Book-1st-Grade-Answer-Key-Chapter-2-Fluency-strategies-within-10-Use-Addition-to-Subtract-Homework-Practice-2.9-Question-26
Think 8 + 1 = 9.
So, 9 – 8 = 1

Conclusion:

Follow Big Ideas Math Grade 1 Answers for the strong foundation. Move with every step of solving the process to solve your problems easily. Get the pdfs of all Big Ideas Math Grade 1 Chapters @bigideasmathanswer.com

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