Big Ideas Math Answers Grade 1 Chapter 4

Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20

In Order to attempt the 1st Grade Exam, you need to have strong fundamentals. Download Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20 free of cost and get the homework help you need. Attempt the practice test to know your preparation level within the Chapter. Practice as much as you can using the Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 and clear the exam with better scores.

Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20

You can make the most out of the Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 through the quick links available. Simply tap on the topic you want and solve various questions involved in it easily. There are various models in addition and subtraction. We have listed all of them by considering enough examples and explained every problem step by step.

Vocabulary

Lesson: 1 Add Doubles from 6 to 10

Lesson: 2 Use Doubles within 20

Lesson: 3 Count on to Add within 20

Lesson 4: Add Three Numbers

Lesson 5 Add Three Numbers by Making a 10

Lesson: 6 Add 9

Lesson 7 Make a 10 to Add

Lesson: 8 Problem Solving: Addition within 20

Performance Task

Add Numbers within 20 Vocabulary

Organize It

Review Words:
addend
doubles
doubles minus 1
doubles plus 1
sum

Use the review words to complete the graphic organizer.

Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 1

Answer:

Explanation:
By Looking at graphic organizer
1.  Here we have 2 blocks and in second block we have one more added,
so we write the review words as doubles plus 1.
2. Here we have only two block so we write the review words as doubles.
3. Here also we have 2 blocks, but in second block on one dot it is crossed,
so we write the review words as doubles minus 1.

Define It

Match the review word to its definition.

Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 2
Answer:

Explanation:
Addend means any of the numbers that are added together.
Sum can be defined as the result or answer we get on adding two or more numbers or terms.
Here 1. 5 + 3 = 8  numbers 5, 3 are addends and 8 is sum
2. 4 + 3 = 7 number 4,3 are addends and 7 is sum.

Lesson 4.1 Add Doubles from 6 to 10

Explore and Grow

Use counters to model the story.

You have 7 marbles. Your friend has 7 marbles. How many marbles are there in all?

Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 3
Answer:
In all, there are total of 14 marbles.

Explanation:
Given I have 7 marbles and my friend has 7 marbles,
The total number of marbles available are ( my marbles and friend’s marble),
7 + 7 = 14 marbles. So 14 marbles are there in all.

Show and Grow

Question 1.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 4
___8____ + ___8___ = __16_____
Answer:
8 + 8 = 16 dots

Explanation:
Given in block 1 we have 8 dots and in block 2 we have 8 dots,
So in total we have 8 + 8 = 16 dots.

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 5
____7___ + __7____ = ___14____
Answer:
7 + 7 = 14 dots

Explanation:
Given in block 1 we have 7 dots and in block 2 we have 7 dots,
So in total we have 7 + 7 = 14 dots.

Question 3.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 6 =
Answer:
9 + 9 = 18 dots

Explanation:
Given in block 1 we have 9 dots and in block 2 we have 9 dots,
So in total we have 9 + 9 = 18 dots.

Question 4.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 7

Answer:
10 + 10 = 20 dots

Explanation:
Given in block 1 we have 10 dots and in block 2 we have 10 dots,
So in total we have 10 + 10 = 20 dots.

Question 5.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 8
____8___ + _8_____ = _______
Answer:
8 + 8 = 16 dots

Explanation:
Given in block 1 we have 8 dots and in block 2 we have 8 dots,
So in total we have 8 + 8 = 16 dots.

Question 6.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 9
___6____ + __6___ = ___12____
Answer:
6 + 6 = 12 dots

Explanation:
Given in block 1 we have 6 dots and in block 2 we have 6 dots,
So in total we have 6 + 6 = 12 dots.

Question 7.
7 + 7 = ___14____
Answer:
7 + 7 = 14 dots

Explanation:
Given first number is 7 and second number is 7,
So in total we have 7 + 7 = 14 dots.

Question 8.
10 + 10 = ___20_____
Answer:
10 + 10 = 20

Explanation:
Given first number is 10 and second number is 10,
So in total we have 10 + 10 = 20.

Question 9.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 10
Answer:

Explanation:
Given first number as 9 and second number as 9,
So in total we have 9 + 9 = 18.

Question 10.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 11
Answer:

Explanation:
Given first number as 8 and second number as 8,
So in total we have 8 + 8 = 16.

Question 11.
MP Reasoning
You and your friend each read 6 books. How many books do you and your friend read in all?
____12______ books
Answer:
Total number of books I and my friend read are 12.

Explanation:
Given I and my friend each read 6 books, that means I read 6 books,
my friend read 6 books, So in total we read 6 + 6 = 12.

Think and Grow: Modeling Real Life

You and your friend have the same number of video games. There are 16 in all. How many video games do you have?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 12
Draw a Picture:

Addition equation: X + X = 16,

___8_______ video games
Answer:
I have 8 number of video games.

Explanation:
Given I and my friend have same number of video games,
So in all both have 16 video games , Let us take I have X number of video games,
means friend will also have X number of video games,
Now addition equation is X + X = 16, 2 X = 16 , So X = 16 ÷ 2 = 8,
So I have 8 video games.

Show and Grow

Question 12.
2 friends give you the same number of pictures. You have 12 in all. How many pictures does each friend give you?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 13
Draw a Picture:

Addition equation:
X + X = 12,

____6______ pictures
Answer:
Each friend gives 6 pictures to me.

Explanation:
Given 2 friends gave me same number of pictures,
So in all both gave 12 pictures , Let us take each gave X number of pictures,
So we write addition equation as X + X = 12, 2 X = 12 , So X = 12 ÷ 2 = 6,
So each friend gave me 6 number of pictures.

Add Doubles from 6 to 10 Practice 4.1

Question 1.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 14
____10______ + ____10______ = ___20______
Answer:
10 + 10 = 20 dots

Explanation:
Given in block 1 we have 10 dots and in block 2 we have 10 dots,
So in total we have 10 + 10 = 20 dots.

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 15
_____6_____ + ____6______ = ____12_____
Answer:
6 + 6 = 12 dots

Explanation:
Given in block 1 we have 6 dots and in block 2 we have 6 dots,
So in total we have 6 + 6 = 12 dots.

Question 3.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 16
Answer:


Explanation:
Given first number as 9 and second number as 9,
So in total we have 9 + 9 = 18.

Question 4.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 17
Answer:

Explanation:
Given first number as 10 and second number as 10,
So in total we have 10 + 10 = 20.

Question 5.
MP Reasoning
You and your friend each do 7 jumping jacks. How many jumping jacks do you and your friend do in all?

____14______ jumping jacks
Answer:
14 jumping jacks I and my friend do in all .

Explanation:
Given I and my friend each do 7 jumping jacks,
means I did 7 jumping jacks, My friend did 7 jumping jacks,
So both overall did 7 + 7 = 14 jumping jacks.

Question 6.
Modeling Real Life
Newton and Descartes each have the same number of treats. They have 18 treats in all.
How many treats does Newton have?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 18

____9______ treats
Answer:
Newton have 9 treats.

Explanation:
Given Newton and Descartes each have the same number of treats,
Suppose if  Newton have  X treats means Descartes have same X treats
and in all both have 18 treats, So X + X = 18 , 2X = 18 , X = 18 ÷ 2 = 9,
So Newton has 9 treats.

Review & Refresh

Use the picture to write an equation.

Question 7.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 19
____3______ + ____2_____ = ____5_____
Answer:
3 + 2 = 5

Explanation:
By seeing the picture there are 3 children sitting and reading books on the chair and
2 children are having bags and going to school, So we write the equation as
3 + 2 = 5.

Question 8.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 20
___5_______ + ____1_____ = ____6_____
Answer:
5 + 1 = 6

Explanation:
By seeing the picture there are 5 children sitting on the ground and reading books,
1 child having book is waving hand, So we write the equation as
5 + 1 = 6.

Lesson 4.2 Use Doubles within 20

Explore and Grow

Use counters to model the story.

You collect 8 leaves. Your friend collects 8 leaves. How many leaves are there in all?

____16_____ leaves
Explanation:
Both I and friend collect same leaves ,
8 + 8 = 16 leaves we call the sum as doubles as both addends are 8.

You collect 1 more leaf. How many leaves are there now?

_____17_____ leaves
Explanation:
We got doubles as 16, Now the required sum is one more than doubles,
That is 17,Therefore 8+8+1= 17 so we call as double plus 1.

Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 21

Show and Grow

Question 1.
Use the double 6 + 6 to find each sum.
6 + 7 = ___13____
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 22
Answer:
6 + 7= 13

Explanation:
We Know the double  6 + 6 = 12 , The number 7 is one more than 6,
So we can write 7 as 6 + 1, The required sum is one more than double,
12 + 1 =13, Sum is 13, therefore 6 + 7 = 13, Double plus 1.

6 + 5 = ___11____
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 23
Answer:
6+5 = 11

Explanation:
We Know the double of 6 + 6 = 12 , The number 5 is one less than 6,
So we can write 5 as 6 – 1, The required sum is one less than double,
12 – 1 = 11, Sum is 11, therefore 6 + 5 = 11, Double minus 1.

Apply and Grow: Practice

Use the double 7 + 7 to find each sum.

Question 2.
7 + 8 = ___15_____
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 24
Answer:
7 + 8 = 15

Explanation:
We know the double of 7 + 7 = 14 , The number 8 is one more than 7,
So we can write 8 as 7 + 1, The required sum is one more than double,
14 + 1 =15, Sum is 15, therefore 7 + 8 = 15, Double plus 1.

7 + 6 = ____13_____
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 25
Answer:
7 + 6 = 13

Explanation:
We know the double of 7+ 7 = 14 , The number 6 is one less than 7,
So we can write 6 as 7 – 1, The required sum is one less than double,
14 – 1 = 13, Sum is 13, therefore 7 + 6 = 13, Double minus 1.

Find the sum. Write the double you used.

Question 3.
5 + 6 = ___11______

___5_+5__+_ ○ ___1___ = ___11____
Answer:
5 + 6 = 11, we use double 5 + 5,

Explanation:
As the first addend is 5 and we know the double is 5 + 5 ,
So 5 + 5 = 10 , The number 6 is one more than 5,
So we can write 6 as 5 + 1, The required sum is one more than double,
10 + 1 =11, Sum is 11, therefore 5 + 6 = 11, Double plus 1.
We use double 5 + 5.

Question 4.
9 + 8 = ___17______

___9+9 -____ ○ ___1____ = __17_____
Answer:
9 + 8 = 17, we use double 9 + 9 ,

Explanation:
As the first addend is 9 and we know the double is 9 + 9,
9 + 9 = 18 , The number 8 is one less than 9,
So we can write 8 as 9 – 1, The required sum is one less than double,
18 – 1 = 17, Sum is 17, therefore 9 + 8 = 17, Double minus 1.
We use double 9 + 9

Question 5.
DIG DEEPER!
Circle two ways you can solve 9 + 10. Show how you know.
9 + 9 and 1 more
9 + 9 and 1 less
10 – 10 and 1 more
10 + 10 and 1 less
Answer:
To solve 9 + 10 the two ways  which we can solve are
9 + 9 and 1 more and other is 10 + 10 and 1 less.

Explanation:
We know 9 + 10 = 19 now we will see which way we can solve,
1. 9 + 9 and 1 more means , it is 18 + 1 which is equal to 19,
Similar to 9 + 10 = 19 , therefore we can solve with 9 + 9 and 1 more .
2. 9 + 9 and 1 less means it is 18 – 1 which is 17,
As 17 is not equal to 9 + 10 = 19, So 9 + 9 and 1 less way we will not solve 9 + 10 .
3. 10 – 10 and 1 more means 0 + 1 = 1 , here this is not equal to 9 + 10,
So by 10 – 10 and 1 more way we will not solve for 9 + 10.
4. 10 + 10 and 1 less means 10 + 9 = 19 which is equal to 9 + 10 ,
So 10 + 10 and 1 less way we will solve 9 + 10.
Therefore to solve 9 + 10 the two ways which we can solve are
9 + 9 and 1 more and other is 10 + 10 and 1 less.

Think and Grow: Modeling Real Life

A music room has 7 keyboards. There is 1 more recorder than keyboards. How many instruments are there?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 26
Which doubles can you use to find the sum?
7 + 7          8 + 8            6 + 6
Equation:

__15_____ instruments
Answer:
There are 15 instruments in the music room.
We use doubles 7 + 7  to find the sum 7 + 8 = 15.

Explanation:
Given a music room has 7 keyboards and there are  1 more recorder than keyboards,
means number of recorders are 7 + 1 = 8, so total number of instruments in room are
7+ 8 = 7 + 7 + 1 = 15, Here we have used doubles 7 + 7.
Therefore  to find the sum we use doubles 7 + 7 and the sum is 7 + 8 = 15.

Show and Grow

Question 6.
A museum has lo paintings. There is 1 fewer sculpture than paintings. How many art pieces are there?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 27
Which doubles can you use to find the sum?
8 + 8        9 + 9      10 + 10
Equation:

____19______ art pieces
Answer:
There are 19 art pieces, We use doubles 10 + 10  to find the sum 10 + 9 = 19.

Explanation:
Given a museum has 10 paintings and there is 1 fewer sculpture than paintings,
means number of sculptures are one less than paintings 10 – 1 = 9,
So total number of art pieces are 10 + 9 = 10 + 10 – 1 = 19,
Here we have used doubles 10 + 10.
Therefore  to find the sum we use doubles 10 + 10 and the sum is 10 + 9 = 19.

Use Doubles within 20 Practice 4.2

Question 1.
9 + 10 = ____19____
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 28
Answer:
9 + 10 = 19, We use double 9 + 9

Explanation:
As the first addend is 9 and we know the double is 9 + 9 ,
So 9 + 9 = 18 , The number 10 is one more than 9,
So we can write 10 as 9 + 1, The required sum is one more than double,
18 + 1 =19, Sum is 19, therefore 9 + 10 = 19, Double plus 1.
Here we have use double 9 + 9

9 + 8 = ____17____
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 29
Answer:
9 + 8 = 17, We use double 9 + 9

Explanation:
As the first addend is 9 and we know the double is 9 + 9,
9 + 9 = 18 , The number 8 is one less than 9,
So we can write 8 as 9 – 1, The required sum is one less than double,
18 – 1 = 17, Sum is 17, therefore 9 + 8 = 17, Double minus 1.
We have use double 9 + 9

Find the sum. Write the double you used.

Question 2.
10 + 9 = ____19_____

____10+10___ -○ ___1____ = __19_____
Answer:
10 + 9 = 19, we use double 10 + 10,

Explanation:
As the first addend is 10 and we know the double is 10 + 10,
10 + 10 = 20 , The number 9 is one less than 10,
So we can write 9 as 10 – 1, The required sum is one less than double,
20 – 1 = 19, Sum is 19, therefore 10 + 9 = 17, Double minus 1.
We have use double 10 + 10 .

Question 3.
7 + 8 = ____15_____

_7_+ 7_+____ ○ __1_____ = ___15___
Answer:
7 + 8 = 15, We use double 7 + 7
Explanation:
As the first addend is 7 and we know the double is 7 +7  ,
So 7 + 7 = 14 , The number 8 is one more than 7,
So we can write 8 as 7 + 1, The required sum is one more than double,
14 + 1 =15, Sum is 15, therefore 7 + 8 = 15, Double plus 1.
We use double 7 + 7.

Question 4.
DIG DEEPER!
Circle two ways you can solve 8 + 9. Show how you know.
8 + 8 and 1 more
8 + 8 and 1 less
9 + 9 and 1 more
9 + 9 and 1 less
Answer:
To solve 8 + 9 the two ways  which we can solve are
8 + 8 and 1 more and other is 9 + 9 and 1 less.

Explanation:
We know 8 + 9 = 17 now we will see which way we can solve,
1. 8 + 8 and 1 more means , it is 16 + 1 which is equal to 17,
Similar to 8 + 9 = 17 , therefore we can solve with 8 + 8 and 1 more .
2. 8 + 8 and 1 less means it is 16 – 1 which is 15,
As 15 is not equal to 8 + 9 = 17, So 8 + 8 and 1 less way we will not solve 8 + 9 .
3. 9 + 9 and 1 more means 18 + 1 = 19 , here this is not equal to 17,
So by 9 + 9 and 1 more way we will not solve for 8 + 9.
4. 9 + 9 and 1 less means 18 -1 = 17 which is equal to sum of 8 + 9  ,
So 9 + 9 and 1 less way we will solve 8 + 9.
Therefore to solve 8 + 9 the two ways which we can solve are
8 + 8 and 1 more and other is 9 + 9 and 1 less.

Question 5.
Modeling Real Life
There are 6 balls. There is 1 more toy hoop than balls. How many toys are there?
Which doubles can you use to find the sum?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 30
7 + 7           8 + 8          6 + 6

___13_____ toys
Answer:
There are 13 toys in total,
We use doubles 6 + 6 to find the sum 6 + 7 = 13.

Explanation:
Given there are 6 balls and there is  1 more toy hoop than balls means
number of toy hoops =  6 + 1 = 7, so total number of toys are
6+ 7 = 6+ 6 + 1 = 13, Here we have used doubles 6 + 6.
Therefore to find the sum we use doubles 6 + 6 and the sum is 6 + 7 = 13.

Review & Refresh

Use the picture to write an equation.

Question 6.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 31
____7____ – ___1____ = ____6____
Answer:
Equation is 7 – 1 = 6

Explanation:
By seeing the picture there are total 7 children in the picture,
6 children are sitting and reading books and one boy with bag on shoulder’s is
walking away from other children, So we write the equation as 7 -1 = 6.

Question 7.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 32
____5____ – ___1____ = ___4_____
Answer:
Equation is 5 – 1 = 4

Explanation:
By seeing the picture there are total 5 children ,
in them four are sitting and playing with toy,
one boy is walking away from others,
So we write the equation as 5 – 1 =4.

Lesson 4.3 Count on to Add within 20

Explore and Grow

Model the story.

There are 8 coins in a piggy bank. You put in 5 more. How many coins are in the bank now?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 33
Answer:
There are 13 coins in the piggy bank.

Explanation:
Given there are 8 coins in a piggy bank and I have put 5 more means,
we start from 8 and move 5 units from 8 on number line we get 13, 8 + 5 = 13,
There are total 13 coins in the piggy bank.

Show and Grow

Question 1.
8 + 4 = _____12_____
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 34
Answer:
8 + 4 = 12

Explanation:
First we start from 8 and move 4 units we get 12 on the number line,
So sum is 8 + 4 = 12 .

Question 2.
5 + 10 = ___15______
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 35
Answer:
5 + 10 = 15

Explanation:
First we start from 5 and move 10 units we get 15 on the number line,
So sum is 5 + 10 = 15 .

Apply and Grow: Practice

Question 3.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36
6 + 8 = _____14_____
Answer:
6 + 8 = 14

Explanation:
First we start from 6 and move 8 units we get 14 on the number line,
So sum is 6 + 8 = 14 .

Question 4.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36
12 + 5 = __17______
Answer:
12 + 5 = 17

Explanation:
First we start from 12 and move 5 units we get 17 on the number line,
So sum is 12 + 5 = 17 .

Question 5.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36
7 + 8 = ___15______
Answer:
7 + 8 = 15

Explanation:
First we start from 7 and move 8 units we get 15 on the number line,
So sum is 7 + 8 = 15 .

Question 6.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36
10 + 9 = ___19_____
Answer:
10 + 9 = 19

Explanation:
First we start from 10 and move 9 units we get 19 on the number line,
So sum is  10 + 9 = 19 .

Question 7.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36
____11___ = 0 + 11
Answer:
11 = 0 + 11 or 0 + 11 = 11

Explanation:
First we start from 0 and move 11 units we get 11 on the number line,
So sum is 11= 0 + 11 or 0 + 11 = 11.

Question 8.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 36
___13_____ = 4 + 9
Answer:
13 = 4 + 9

Explanation:
First we start from 4 and move 9 units we get 13 on the number line,
So sum is 13= 4 + 9  or 4 + 9 = 13.

Question 9.
MP Structure
Write the equation shown by the number line. Then write the equation another way.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 37
Answer:
7 + 4 = 11     or  4 + 7 = 11 or 11 = 7 + 4

Explanation:
As shown in the number line we are starting from 7
and moving 4 units we get 11,
So the equation is 7 + 4 = 11, we can also write  the equation as 4 + 7 =11,
there is no change in the value of sum.
We get sum 11 if we add 7 and 4.

Think and Grow: Modeling Real Life

You have 7 train cars. Newton has 5 more than you. Descartes has 4 more than you. Who has more train cars, Newton or Descartes?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 38
Model:
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 39

Equations:
Newton               Descartes
7 + 5 = 12          7 + 4 = 11

Who has more?         Newton             Descartes
Newton has more trains.

Explanation:
Given I have 7 trains, Newton has 5 more than you,
So the equation is 7 + 5 = 12, Newton has 12 trains,
and Descartes has 4 more than me , the equation is
7 + 4 = 11, Descartes has 11 trains. Now we compare with
Newton and Descartes so in between 12 and 11 we compare,
as 12 is more or greater than 11, means Newton has more trains = 12.

Show and Grow

Question 10.
You have 6 comic books. Newton has 5 more than you. Descartes has 6 more than you. Who has more comic books, Newton or Descartes?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 40
Model:
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 39

Equations:
Newton             Descartes
6 + 5 = 11          6 + 6 = 12

Who has more?         Newton             Descartes
Descartes has more comic books.

Explanation:
Given I have 6 comic books , Newton has 5 more than you,
So the equation is 6 + 5 = 11, Newton has 11 comic books,
and Descartes has 6 more than me , the equation is
6 + 6 = 12, Descartes has 12 comic books. Now we compare with
Newton and Descartes so in between 11 and 12 we compare,
as 12 is more or greater than 11, means Descartes has more comic books = 12.

Count on to Add within 20 Practice 4.3

Question 1.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41
10 + 7 = ___17_______
Answer:
10 + 7 = 17

Explanation:
First we start from 10 and move 7 units we get 17 on the number line,
So sum is 10 + 7 = 17.

Question 2.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41
8 + 9 = ____17_____
Answer:
8 + 9 = 17

Explanation:
First we start from 8 and move 9 units we get 17 on the number line,
So sum is 10 + 7 = 17.

Question 3.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41
_____15_____ = 6 + 9
Answer:
6 + 9 = 15 or 15 = 6 + 9

Explanation:
First we start from 6 and move 9 units we get 15 on the number line,
So sum is 6 + 9 = 15 or 15 = 6 + 9.

Question 4.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 41
______16_____ = 12 + 4
Answer:
16= 12 + 4 or 12 + 4 = 16

Explanation:
First we start from 12 and move 4 units we get 16 on the number line,
So sum is  12 + 4 = 16 or 16 = 12 + 4.

Question 5.
MP Structure
Write the equation shown by the number line. Then write the equation another way.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 42
Answer:
5 + 8 = 13  or  8 + 5 = 13 or 13 = 5 + 8

Explanation:
As shown in the number line we are starting from 5
and moving 8 units we get 13,
So the equation is 5 + 8 = 13, we can also write  the equation as 8 + 5 =13,
there is no change in the value of sum.
We get sum 13 if we add 5 and 8.

Question 6.
Modeling Real Life
You have 11 toys. Newton has 3 more than you. Descartes has 6 more than you. Who has more toys, Newton or Descartes?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 43
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 44
Answer:
Equations:     Newton             Descartes
11 + 3 = 14          11 + 6 = 17
Descartes has more toys than Newton

Explanation:
Given I have 11 toys , Newton has 3 more than you,
So the equation is 11 + 3 = 14, Newton has 14 toys,
and Descartes has 6 more than me , the equation is
11 + 6 = 17, Descartes has 17 toys. Now we compare with
Newton and Descartes so in between 14 and 17 toys if  we compare
we get 17 is more or greater than 14, means Descartes has more toys = 17.

Review & Refresh

Question 7.
Circle the triangle. Draw a rectangle around the hexagon.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 45
Answer:

Explanation:
We know triangle means a closed, two-dimensional shape with three straight sides.
In shapes given in figure we have triangle in green so we will circle it,
and we know hexagon can be defined as a polygon with six sides.
In shapes given in the figure we have hexagon in yellow,
So we draw a rectangle around the hexagon.

Question 8.
Circle the cube. Draw a rectangle around the sphere.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 46
Answer:

Explanation:
Cube means a symmetrical three-dimensional shape,
either solid or hollow, contained by six equal squares,
In figure we have cube in purple so we circle the cube.
Sphere means a round solid figure, or its surface,
with every point on its surface equidistant from its center.
In the shapes given in figure we have sphere in yellow,
So we draw a rectangle around hexagon.

Lesson 4.4 Add Three Numbers

Explore and Grow

Use linking cubes to model the story.

You have 5 red pencils, 4 yellow pencils, and 3 blue pencils. How many pencils do you have in all?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 47
Answer:

Explanation:
Given 5 red pencils , 4 yellow pencils  and 3 blue pencils,
a. Now by using linking the cubes first we link with 5 red and 4 yellow pencils
we get 5 + 4 = 9 pencils now we link with 3 blue pencils 9 + 3 = 12 pencils.
b. Now by using linking the cubes first we link with 4 yellow pencils and 3 blue pencils
we get 4 + 3 = 7 pencils now we link with 5 red pencils 7 + 5 = 12 pencils.
c. Now by using linking the cubes first we link with 5 red and 3 blue pencils
we get 5 + 3 = 8 pencils now we link with 4 yellow pencils 8 + 4 = 12 pencils.
In all we have 12 pencils.

Show and Grow

Question 1.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 48
Answer:

Explanation:
By using linking the cubes
a. First we add 2 + 5 = 7 and now we add 7+ 6 we get 13.
b. Here we add 5 + 6 =11, now we add 11 + 2 =13
c. Now here we add first 2 with 6 we get 8 to 8 we add 5
we will get 8 + 5 = 13, So we get sum as 13.

Question 2.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 49
Answer:

Explanation:
By using linking the cubes
a. First we add 4 + 4 = 8 and now we add 8+ 3 we get 11.
b. Here we add 3 + 4 =7, now we add 7 + 4 =11
c. Now here we add first 4 with 3 we get 7 to 7 we add 4
we will get 7 + 4 = 11, So we get sum as 11.

Apply and Grow: Practice

Question 3.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 50
Answer:

Explanation:
By using linking the cubes
a. First we add 3 + 3 = 6 and now we add 6+ 5 we get 11.
b. Here we add 3 + 5 =8, now we add 8 + 3 =11
c. Now here we add first 5 with 3 we get 8 to 8 we add 3
we will get 8 + 3 = 11, So we get sum as 11.

Question 4.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 51
Answer:

Explanation:
By using linking the cubes
a. First we add 3 + 1 = 4 and now we add 4+ 2 we get 6.
b. Here we add 1 + 2 =3, now we add 3 + 3 =6,
c. Now here we add first 3 with 2 we get 5 to 5 we add 1
we will get 5 + 1 = 6, So we get sum as 6.

Question 5.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 52
Answer:

Explanation:
By using linking the cubes
a. First we add 7 + 5 = 12 and now we add 12+ 5 we get 17.
b. Here we add 5 + 5 =10, now we add 10 + 7 = 17,
c. Now here we add first 7 with 5 we get 12 to 12 we add 5
we will get 12 + 5 = 17, So we get sum as 17.

Question 6.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 53
Answer:

Explanation:
By using linking the cubes
a. First we add 4 + 5 = 9 and now we add 9 + 2 we get 11.
b. Here we add 5 + 2 = 7, now we add 7 + 4 = 11,
c. Now here we add first 4 with 2 we get 6 to 6 we add 5
we will get 6 + 5 = 11, So we get sum as 11.

Question 7.
7 + 8 + 1 = _________
Answer:
7 + 8 +1 = 16

Explanation:
By using linking the cubes
a. First we add 7 + 1 = 8 and now we add 8 + 8 we get 16.
b. Here we add 7 + 8 = 15, now we add 15 + 1 = 16,
c. Now here we add first 8 with 1 we get 9 to 9 we add 7
we will get 9 + 7 = 16, So we get sum as 16.

Question 8.
8 + 6 + 2 = _________
Answer:
8 + 6 + 2 = 16

Explanation:
By using linking the cubes
a. First we add 8 + 2 = 10 and now we add 10 + 6 we get 16.
b. Here we add 8 + 6 = 14, now we add 14 + 2 = 16,
c. Now here we add first 6 with 2 we get 8 to 8 we add
8 we will get 8 + 8 = 16, So we get sum as 16.

Question 9.
4 + 9 + 4 = __________
Answer:
4 + 9 + 4 = 17

Explanation:
By using linking the cubes
a. First we add 4 + 4 = 8 and now we add 8 + 9 we get 17.
b. Here we add 4 + 9 = 13, now we add 13 + 4 = 17,
c. Now here we add first 9 with 4 we get 13 to 13 we add 4
we will get 13 + 4 = 17, So we get sum as 17.

Question 10.
DIG DEEPER
Complete the number puzzle so that each branch has a sum of 14.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 54
Answer:

Explanation:
Let us take the missing number as X, Y Z, P
We take 6 + 1 + ___X___ = 14 , means X = 7 + X = 14,
therefore X = 14 – 7 = 7, So 6 + 1 + 7 = 14,
Next  Y, 5 + Y + 6 = 14 , 11 + Y = 14 , Y = 14 -11,
We get Y = 3,Making 5 + 3 + 6 = 14
Now Z, 6 + 7 + Z = 14, 13 + Z = 14, Z = 14 – 13,
Z = 1 Making 6 + 7 + 1 = 14
Now P, 4 + P + 3 = 14, 7 + P = 14 ,P = 14 – 7,
We get P = 7 making  4 + 7 + 3 = 14.

Think and Grow: Modeling Real Life

You have 6 goldfish, 7 minnows, and 6 guppies. Will the tank hold all of your fish?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 55
Equation:
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 56

Show how you know:
Answer:

Explanation:
Given I have 6 goldfish, 7 minnows and 6 guppies, Total Number of
Fishes with me are  6 + 7 + 6 = 19 , No the tank can not hold
all of fishes as given in the figure a tank can hold 15 Fish and
I have 19 which are more than 15 ,
No, it is not possible for the tank to hold 19 Fish.

Show and Grow

Question 11.
You have 2 lovebirds, 4 canaries, and 3 finches. Will the cage hold all of your birds?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 57
Equation:
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 58

Show how you know:
Answer:

Explanation:
Given I have 2 lovebirds, 4 canaries, and 3 finches ,
Total Number of birds I have are 2 + 4 + 3 = 9,
Now as shown in the picture a cage can holds 10 birds,
We have total 9 birds which is less than 10 means,
Yes, the cage can hold all of my birds .

Add Three Numbers Practice 4.4

Question 1.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 59
Answer:

Explanation:
By using linking the cubes
a. First we add 2 + 2 = 4 and now we add 6 + 4 we will get 10.
b. Here we add first 6 + 2 = 8, now we add 8 + 2 = 10,
c. Now here we add 6 with 2 we get 8 to 8 we add 2,
we will get  8 + 2 = 10, So we get sum as 10.

Question 2.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 60
Answer:

Question 3.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 61
Answer:

Explanation:
By using linking the cubes
a. First we add 8 + 7 = 15 and now we add 15 + 4 we will get 19.
b. Here we add first 7 + 4 = 11, now we add 8 + 11 = 19,
c. Now here we add 8 with 4 we get 12 to 12 we add 7,
we will get  12 + 7 = 19, So we get sum as 19.

Question 4.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 62
Answer:

Explanation:
By using linking the cubes
a. First we add 9 + 1 = 10 and now we add 10 + 10 we will get 20.
b. Here we add first 9 + 10 = 19, now we add 19 + 1 = 20,
c. Now here we add 10 with 1 we get 11 to 11 we add 9,
we will get  11 + 9 = 20, So we get sum as 20.

Question 5.
3 + 4 + 5 = _________
Answer:

Explanation:
By using linking the cubes
a. First we add 3 + 5 = 8 and now we add 8 + 4 we will get 12.
b. Here we add first 3 + 4 = 7, now we add  7 and 5 as 7 + 5 = 12,
c. Now here we add 4 with 5 we get 9 to 9 we add 3,
we will get  3 + 9 = 12, So we get sum as 12.

Question 6.
7 + 5 + 5 = ________
Answer:

Explanation:
By using linking the cubes
a. First we add 7 + 5 = 12 and now we add 12 + 5 we will get 17.
b. Here we add first 7 + 5 = 12, now we add  12 and 5 as 12 + 5 = 17,
c. Now here we add 5 and 5 we get 10, we add 7 to 10,
we will get  7 + 10 = 17, So we get sum as 17.

Question 7.
8 + 4 + 8 = ________
Answer:

Explanation:
By using linking the cubes
a. First we add 8 + 8 = 16 and now we add 16 + 4 we will get 20.
b. Here we add first 8 + 4 = 12, now we add 12 and 8 as 12 + 8 = 20,
c. Now here we add 4 with 8 we get 12 ,we add 8 to 12,
we will get  8 + 12 = 20, So we get sum as 20.

Question 8.
DIG DEEPER!
Complete the number puzzle so that each branch has the sum of 13.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 63
Answer:

Explanation:
Let us take the missing number as X, Y Z, P
We take 5 + 1 + ___X___ = 13 , means X = 6 + X = 13,
therefore X = 13 – 6 = 7, So 5 + 1 + 7 = 13,
Next  Y, 1 + Y + 6 = 13 , 7 + Y = 13, Y = 13 – 7,
We get Y = 6,Making 1 + 6 + 6 = 13
Now Z, 4 + 5 + Z = 13, 9 + Z = 13, Z = 13 – 9,
Z = 4 Making 4 + 5 + 4 = 13
Now P, 7 + P + 2 = 13, 9 + P = 13 ,P = 13 – 9,
We get P = 4 making  7 + 4 + 2 = 13.

Question 9.
Modeling Real Life
You have 7 white chickens, I black chicken, and 8 brown chickens. Will the chicken coop hold all of your chickens?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 64
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 65

Show how you know:
Answer:

Explanation:
Given I have 7 white chickens, 1 black chicken and 8 brown chickens,
Total Number of  chickens with me are  7 + 1 + 8 = 16 ,
Given in the figure a chicken coop can hold 15 chickens and
I have 16 which is more than 15.
No, it is not possible for the chicken coop to hold all 16 chickens.

Review & Refresh

Question 10.
5 + __5__ = 10
Answer:
5 + 5 = 10

Explanation:
Let us take the missing number as X,
It is given in the equation that 5 + X = 10,
So X = 10 – 5 = 5, means 5 + 5 = 10.

Question 11.
10 = 6 + ___4___
Answer:
10 = 6 + 4

Explanation:
Let us take the missing number as X,
It is given in the equation that 10 = 6 + X,
So X = 10 – 6 = 4, means 10 = 6 + 4 .

Question 12.
8 + __2___ = 10
Answer:
8 + 2 = 10

Explanation:
Let us take the missing number as X,
It is given in the equation that 8 + X = 10,
So X = 10 – 8 = 2, means 8 + 2 = 10.

Question 13.
10 = 3 + __7___
Answer:
10 = 3 + 7

Explanation:
Let us take the missing number as X,
It is given in the equation that 10 = 3 + 7,
So X = 10 – 3 = 7, means 10 = 3 + 7.

Lesson 4.5 Add Three Numbers by Making a 10

Explore and Grow

Show three ways to find a sum.
4 + 3 + 7 = ________

4 + 3 + 7 = ________

4 + 3 + 7 = ________
Answer:
4 + 3 + 7 = 14

Explanation:
By using the three ways we find sum,
Way 1. First we add 4 + 7 = 11 and now we add 11 + 3 we will get 14.
Way 2. Here we add first 4 + 3 = 7, now we add 7 and 7 as 7 + 7 = 14,
Way 3. Now here we add 3 with 7 we get 10 to 10 we add 4,
we will get  4 + 10 = 14, So we get sum as 14.

Show and Grow

Make a 10 to add.

Question 1.

Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 66

Answer:

Add 9,1 first to make 10 then add 3, sum = 9 + 1 + 3 = 13

Explanation:
To make 10 first we see adding 9 + 1 = 10 is equal to 10,
next we add 1 +3 =4 not equal to 10, 9 + 3 = 12 which
is not equal to 10 ,So to make 10 we add  9,1 first, then add 3,
So the sum is 9 + 1 + 3 = 13.

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 67
Answer:

Add 2,8 first to make 10 then add 4, sum = 4 + 2 + 8 = 14

Explanation:
To make 10 first we see adding 4 + 2 = 6,
6 is not equal to 10, 2 + 8 = 10 which is equal to 10 ,
and now we add 4 + 8 = 12 which is not equal to 10,
So to make 10 we add 2,8 first then add 4
So the sum is 4 + 2 + 8 = 14.

Question 3.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 68
Answer:

Add 3,7 first to make 10 then add 2, sum = 2 + 3 + 7 = 12

Explanation:
To make 10 first we see adding 2 + 3 = 5,
5 is not equal to 10, 3 + 7 = 10 which is equal to 10 ,
and now we add 2 + 7 = 9 which is not equal to 10,
So to make 10 we add 3,7 first and then add 2
So the sum is 2 + 3 + 7 = 12.

Question 4.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 69
Answer:

Add 5,5 first to make 10 then add 9, sum = 5 + 5 + 9 = 19

Explanation:
To make 10 first we see adding 5 + 5 = 10,
so is equal to 10, now we add 5 + 9 = 14  which is not equal to 10 ,
and now we add other 5 + 9 = 14 which is also not equal to 10,
So to make 10 we add 5,5 first and then add 9,
So the sum is 5 + 5 + 9 = 19.

Apply and Grow: Practice

Make a 10 add.

Question 5.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 70
Answer:

Add 3,7 or 7,3 first to make 10 then add 3, sum = 3 + 7 + 3 = 13

Explanation:
To make 10 first we see adding 3 + 7 = 10,
so is equal to 10, now we add 7 + 3 = 10  which is also equal to 10 ,
and now we add other 3 + 3 = 6 which is not equal to 10,
So to make 10 we add 3,7 or 7,3 first and then add 3
So the sum is 3 + 7 + 3 = 13.

Question 6.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 71
Answer:

Add 8,2 first to make 10 then add 6, sum = 8 + 6 + 2 = 16

Explanation:
To make 10 first we see adding 8 + 6 = 14,
14 is not equal to 10, now we add 6 + 2 = 8  which is not equal to 10 ,
and now we add 8 + 2 = 10 which is equal to 10,
So to make 10 we add 8,2 first and then add 6
So the sum is 8 + 6 + 2 = 16.

Question 7.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 72
Answer:

Add 6,4 first to make 10 then add 7, sum = 6 + 7 + 4 = 17

Explanation:
To make 10 first we see adding 6 + 7 = 13,
It is not equal to 10, now we add 7 + 4 = 11  which is not equal to 10 ,
and now we add 6 + 4 = 10 which is equal to 10,
So to make 10 we add 6,4 first then add 7
So the sum is 6 + 7 + 4 = 17.

Question 8.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 73
Answer:

Add 5,5 first to make 10 then add 8, sum = 8 + 5 + 5 = 18

Explanation:
To make 10 first we see adding 8 + 5 = 13,
It is not equal to 10, now we add 5 + 5 = 10  which equal to 10 ,
and now we add 8 + 5 = 13 which is not equal to 10,
So to make 10 we add 5,5 first then add 8
So the sum is 8 + 5 + 5 = 18.

Question 9.
4 + 6 + 2 = ________
Answer:

Add 4,6 first to make 10 then add 2, sum = 4 + 6 + 2 = 12

Explanation:
To make 10 first we see adding 4 + 6 = 10,
which is equal to 10, now we add 6 + 2 = 8  which is not equal to 10 ,
and now we add 4 + 2 = 6 which is not equal to 10,
So to make 10 we add 4,6 first then add 2
So the sum is 4 + 6 + 2 = 12.

Question 10.
5 + 9 + 1 = ________
Answer:

Add 9,1 first to make 10 then add 5, sum = 5 + 9 + 1 = 15

Explanation:
To make 10 first we see adding 5 + 9 = 14,
which is not equal to 10, now we add 9 + 1 = 10  which is equal to 10 ,
and now we add 5 + 1 = 6 which is not equal to 10,
So to make 10 we add 9,1 first then add 5,
So the sum is 5 + 9 + 1 = 15.

Question 11.
DIG DEEPER!
What do you know about the missing addends and the sum?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 74
Answer:
We know the sum of the missing addends is 10 and the total sum is 10 + 3 = 13.

Explanation:
From the picture it is showing that if we add the missing
addends we get sum as 10 and the total sum is 10 + 3 = 13.
So whenever we are adding two missing addends we should always check,
their sum should be always 10, Example if one number is 1
other numbers will be 10-1 = 9. So the missing numbers are (1,9).
It can be even (2,8), (3,7),(4,6),(5,5),(6,4),(7,3),(8,2) or (9,1).

Think and Grow: Modeling Real Life

You need to knock down 20 pins to win. Do you win?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 75
Equation:
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 76
Show how you know:
Answer:

6 + 3 + 7 = 16, No we will not win.

Explanation:
Given pins as 6,3,7 if we add all we get 6 + 3 + 7 = 16,
we need 20 pins to knock down to win and we got 16 which are less than 20,
So no we will not win.

Show and Grow

Question 12.
Your hockey team needs 12 goals to break a record. Does your team break the record?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 77
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 78
Equation:
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 79
Show how you know:
Answer:

5 + 6 + 4 = 15, Yes my hockey team will break the record.

Explanation:
Given the goals made are 5,6,4 so the total number of goals
made are 5 + 6 + 4 = 15, to break hockey record
we need 12 goals as my team made 15 goals which is more than 12,
Yes my hockey team will break the record.

Add Three Numbers by Making a 10 Practice 4.5

Make a 10 to add.

Question 1.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 80
Answer:

Add 6,4 first to make 10 then add 8, sum = 6 + 8 + 4 = 18

Explanation:
To make 10 first we see adding 6 + 8 = 14,
which is not equal to 10, now we add 8 + 4 = 12
which is not equal to 10 ,
and now we add 6 + 4 = 10 which is equal to 10,
So to make 10 we add 6,4 first then add 8,
So the sum is 6 + 8 + 4 = 18.

Question 2.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 81
Answer:

Add 3,7 first to make 10 then add 4, sum = 3 + 7 + 4 = 14

Explanation:
To make 10 first we see adding 3 + 7 = 10,
which is equal to 10, now we add 7 + 4 = 11
which is not equal to 10 ,
and now we add 3 + 4 = 7 which is not equal to 10,
So to make 10 we add 3,7 first then add 4,
So the sum is 3 + 7 + 4 = 14.

Question 3.
5 + 8 + 2 = _______
Answer:

Add 8,2 first to make 10 then add 5, sum = 5 + 8 + 2 = 15

Explanation:
To make 10 first we see adding 5 + 8 = 13,
which is not equal to 10, now we add 8 + 2 = 10
which is equal to 10 ,
and now we add 5 + 2 = 7 which is not equal to 10,
So to make 10 we add 8,2 first then add 5,
So the sum is 5 + 8 + 2 = 15.

Question 4.
1 + 9 + 7 = _________
Answer:

Add 1,9 first to make 10 then add 7, sum = 1 + 9 + 7 = 17

Explanation:
To make 10 first we see adding 1 + 9 = 10,
which is equal to 10, now we add 9 + 7 = 16
which is not equal to 10 ,
and now we add 1 + 7 = 8 which is not equal to 10,
So to make 10 we add 1,9 first then add 7,
So the sum is 1 + 9 + 7 = 17.

Question 5.
DIG DEEPER!
What do you know about the missing addends and the sum?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 82
Answer:
we know the sum of the missing addends is 10 and the total sum is 10 + 2 = 12.

Explanation:
From the picture it is showing that if we add the missing
addends we get sum as 10 and the total sum is 10 + 2 = 12.
So whenever we are adding two missing addends we should always check,
their sum should be always 10, Example if one number is 2
other number will be 10-2 = 8. So the missing addends here are (2,8).
It can be (1,9),(3,7),(4,6),(5,5),(6,4),(7,3),(8,2) or (9,1).

Question 6.
Modeling Real Life
Your baseball team needs 15 runs to break a record. Does your team break the record?
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 83
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 84
Equation:
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 85
Show how you know:
Answer:

6 + 4 + 6 = 16, Yes my team will break the record.

Explanation:
Given my team makes 6,4,6 runs so total runs made are
6 + 4 + 6 = 16, to break the record we require 15 runs
but the team made 16 as 16 is more than 15,
Yes, my team will break the record.

Review & Refresh

Circle the heavier object.

Question 7.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 86
Answer:

Explanation:
By looking at the pictures book is heavier than a pencil.
So the book is circled.

Question 8.
Big Ideas Math Answer Key Grade 1 Chapter 4 Add Numbers within 20 87
Answer:

Explanation:
By looking at the pictures apple is heavier than the feather,
So apple is circled.

Lesson 4.6 Add 9

Explore and Grow

Use counters and the ten frames to find the sum. Show how you can make a lo to solve.

Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 88
Answer:
9 + 1 + 4 = 14

Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have add 1 to 9 now we will minus 1 from 5 we get 5 – 1 = 4,
Now we write the total sum as 9 + 1 + 4 = 14 .

Show and Grow

Make a 10 to add.

Question 1.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 89
Answer:

Sum is 9 + 1 + 2 = 12  or  9 + 3 = 12.

Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have to  add 1 to 9 now  we will minus 1 from 3 we get 3 – 1 = 2,
Now we write the total sum as 9 + 1 + 2 = 12  or 9 + 3 = 12.

Question 2.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 90
Answer:

Sum is 9 + 1 + 5 = 15 or 9 + 6 = 15.
Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have to  add 1 to 9 now  we will minus 1 from 6 we get 6 – 1 = 5,
Now we write the total sum as 9 + 1 + 5 = 15 or 9 + 6 = 15.

Apply and Grow: Practice

Make a 10 to add.

Question 3.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 91
Answer:

Sum is 9 + 1 + 1 = 11  or 9 + 2 = 11.

Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have to  add 1 to 9 now  we will minus 1 from 2 we get 2 – 1 = 1,
Now we write the total sum as 9 + 1 + 1 = 11  or 9 + 2 = 11.

Question 4.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 92
Answer:

Sum is 9 + 1 + 8 = 18  or 9 + 9 = 18.

Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have to add 1 to 9 now  we will minus 1 from 9 we get 9 – 1 = 8,
Now we write the total sum as 9 + 1 + 8 = 18  or 9 + 9 = 18.

Question 5.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 93
Answer:

Sum is 9 + 1 + 4 = 14 or 9 + 5 = 14.

Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have to add 1 to 9 now  we will minus 1 from 5 we get 5 – 1 = 4,
Now we write the total sum as 9 + 1 + 4 = 14 or 9 + 5 = 14.

Question 6.
DIG DEEPER!
Use the ten frame to complete the equations.
9 + ? = 17
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 94
10 + _______ = 17
So, 9 + ________ = 17
Answer:
10 + 7 = 17,
So  9 + 1 + 7 = 17

Explanation:
Given 10 + ____ = 17, to find the missing number we take it as X,
10 + X = 17 , X = 17 – 10 =7. So the equation is 10 + 7 = 17.
Now we write 10 as 9 + 1 by using ten frame and
add 7 so the total sum is 9 + 1 + 7 = 17 or 10 + 7 = 17.

Think and Grow: Modeling Real Life

You have 9 stickers and earn 5 more. Your friend has 6 stickers and earns 10 more. Do you and your friend have the same number of stickers?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 95
Addition equations:
you                Friend
9 + 5 = 14          6 + 10 = 16

Yes       No

Show how you know:
Answer:
My equation is 9 + 5 = 14 and friend has 6 + 10 =16
as 14 is not equal to 16, so I and my friend don’t
have the same number of stickers.

Explanation:
Given I have 9 stickers and earn 5 more means in total I have 9 + 5 = 14 stickers and friend has 6 stickers and earns 10 more means in total friend have 6 + 10 = 16 stickers,
Now comparing between me and my friend as 14 and 16 are not same, So No, I and my friend do not have the same number of stickers.

Show and Grow

Question 7.
Your friend has 9 magnets and finds 6 more. You have 5 magnets and find 10 more. Do you and your friend have the same number of magnets?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 96
Addition equations:
 you             Friend
5 + 10 =15      9 + 6 = 15

Yes       No

Show how you know:

Answer:
My equation is 5 + 10 = 15 and friend equation is 9 + 6 = 15,
as both are equal, So Yes, I and my friend have the same number of magnets.

Explanation:
Given I have 5 magnets and find 10 more means in total, I have 5 + 10 = 15 magnets and friend has 9 magnets and finds 6 more means in total friend have 9 + 6 = 15 magnets, Now comparing between me and my friend as 15 and 15 are same, So Yes, I and my friend have the same number of magnets.

Add 9 Practice 4.6

Make a 10 to add

Question 1.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 97
Answer:

Sum is 9 + 1 + 2 = 12 or 9 + 3 = 12.

Explanation:
First we make sum 10, For 9 to make 10 we need 10-9=1,
as we have to add 1 to 9 now we will minus 1 from 3 we get 3 – 1 = 2,
Now we write the total sum as 9 + 1 + 2 = 12 or 9 + 3 = 12.

Question 2.
DIG DEEPER!
Use the ten frame to complete the equations.
16 = ? + ?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 98
10 + ___6_____ = ___16____
So, 16 = __9 +__1____ + __6___.
Answer:
We write the equation as 16 = 10 + 6
So 16 =  9 + 1 + 6 or 16 = 10 + 6

Explanation:
Given 10 + ____ = 16, to find the missing number we take it as X,
10 + X = 16 , X = 16 – 10 =6. So the equation is 10 + 6 = 16.
Now we write 10 as 9 + 1 by using the ten frame
and add 6 so the total sum is 9 + 1 + 6 = 16 or 10 + 6 = 16.

Question 3.
Modeling Real Life
You have 9 rocks and collect 7 more. Your friend has 8 rocks and collects 8 more. Do you and your friend have the same number of rocks?
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 99
Yes             No
Show how you know:
Answer:
I have 9 + 7 = 16 rocks,
Friend have 8 + 8 = 16 rocks,
Yes, I and my friend have the same number of rocks.

Explanation:
Given I have 9 rocks and collected 7 more,
So I have total 9 + 7 = 16 rocks and my friend have 8 rocks and collects 8 rocks total he have 16 rocks,
Now comparing both me and my friend both have the equal number of rocks, Yes, I and my friend have the same number of rocks.

Review & Refresh

Circle the longer object.

Question 4.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 100
Answer:

Explanation:
By seeing the picture we can identify yellow spectacles are longer than the red spectacles, So circled the yellow spectacles.

Question 5.
Big Ideas Math Answers 1st Grade 1 Chapter 4 Add Numbers within 20 101
Answer:

Explanation:
By seeing the picture we can identify tooth paste is longer than the toothbrush, So circled the toothpaste.

Lesson 4.7 Make a 10 to Add

Explore and Grow

Use counters and the ten frame to find the sum.
Show how you can make a lo to solve.

Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 102
Answer:

Explanation:
First we make sum 10, For 8 to make 10 we need 10-8=2,
as we have to add 2 to 8 now we will minus 2 from 6 we get 6 – 2 = 4,
Now we write the total sum as 8 + 2 + 4 = 14.

Show and Grow

Make a 10 to add.

Question 1.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 103
Answer:

Sum as 8 + 2 + 3 = 13 or 8 + 5 = 13.

Explanation:
First we make sum 10, For 8 to make 10 we need 10-8=2,
as we have to add 2 to 8 now we will minus 2 from 5 we get 5 – 2 = 3,
Now we write the total sum as 8 + 2 + 3 = 13 or 8 + 5 = 13.

Question 2.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 104
Answer:

Sum as 7 + 3 + 4  = 14 or 7 + 7 = 14.

Explanation:
First, we make sum 10, For 7 to make 10 we need 10-7=3,
as we have to add 3 to 7 now we will minus 3 from 7 we get 7 – 3 = 4,
Now we write the total sum as 7 + 3 + 4  = 14 or 7 + 7 = 14.

Apply and Grow: Practice

Make a 10 to add.

Question 3.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 105
Answer:

Sum as 7 + 3 + 3  = 13 or 7 + 6 = 13.

Explanation:
First we make sum 10, For 7 to make 10 we need 10-7=3,
as we have to add 3 to 7 now we will minus 3 from 6 we get 6 – 3 = 3,
Now we write the total sum as 7 + 3 + 3  = 13 or 7 + 6 = 13.

Question 4.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 106
Answer:

Sum as 7 + 3 + 1  = 11 or 7 + 4 = 11.

Explanation:
First we make sum 10, For 7 to make 10 we need 10-7=3,
as we have to add 3 to 7 now we will minus 3 from 4 we get 4 – 3 = 1,
Now we write the total sum as 7 + 3 + 1  = 11 or 7 + 4 = 11.

Question 5.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 107
Answer:

Sum as 8 + 2 + 5 = 15 or 8 + 7 = 15.

Explanation:
First we make sum 10, For 8 to make 10 we need 10-8=2,
as we have to add 2 to 8 now we will minus 2 from 7 we get 7 – 2 = 5,
Now we write the total sum as 8 + 2 + 5 = 15 or 8 + 7 = 15.

Question 6.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 108
Answer:

Sum as 6 + 4 + 2 = 12 or 6 + 6 = 12.
Explanation:
First we make sum 10, For 8 to make 10 we need 10-6=4,
as we have to add 4 to 6 now we will minus 4 from 6 we get 6 – 4 = 2,
Now we write the total sum as 6 + 4 + 2 = 12 or 6 + 6 = 12.

Question 7.
MP Number Sense
Use 4, 7, and 10 to complete the sentence.
7 + ___7_____ has the same sum as ___4___ + __10_____.
Answer:
7 + 7  has the same sum as  4 + 10

Explanation:
Given to use numbers 4,7,10 to make the sentence
7 +  _____ = ________ + _______ both sides sum is same
As left side 7 is given we substitute and check first we use 4, then 7 and 10
7 +  4 = 11 now we have numbers 7 and 10, sum is 7+10 = 17
So (7 + 4)= 11  ≠ (7 + 10) =17, next we take 7 and check 7 + 7 = 14
now we have numbers 4 , 10 and sum is 4 + 10 = 14
So (7 + 7) = 14 = (4 + 10) = 14 here if we take for 7 left side and 4,10 right
we get same sum both side, now we  even check taking 10 first,
7 + 10 = 17 in left side and we have numbers 7 and 4 for right as 7 + 4 =11,
So (7 + 10)= 17 ≠ (7 + 4) =11, So to make both the same sum
we take left side number as 7 and right side numbers 4, 10
making the sentence as (7 + 7) = (4 + 10) = 14.

Think and Grow: Modeling Real Life

There are 8 crabs. 7 more join them. There are 10 turtles. 5 more join them.
Is the number of crabs the same as the number of turtles?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 109
Addition equations:
Yes              No
Show how you know:
Answer:
Addition equations:
Crabs                 Turtles
8 + 7 = 15          10 + 5 =15
Yes, the number of crabs are the same as the number of turtles.

Explanation:
Given 8 crabs and 7 more joined them so the number of crabs are 8 + 7 = 15 crabs and there are 10 turtles and 5 more joined them
So the total number of turtles are 10 + 5 = 15 turtles, as both are 15,
Yes, the number of crabs are the same as the number of turtles.

Show and Grow

Question 8.
There are 6 squirrels. 6 more join them. There are 10 birds. 2 more join them. Is the number of squirrels the same as the number of birds?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 110
Addition equations:
Yes               No
Show how you know:
Answer:
Squirrels          Birds
6 + 6 = 12    10 + 2 = 12
Yes, the number of squirrels are the same as the number of birds.

Explanation:
Given 6 squirrels and 6 more joined them so total squirrels are 6 + 6 = 12 and 10 birds, 2 more birds joined making total as 10 + 2 = 12 birds as both are 12,
Yes, the number of squirrels are the same as the number of birds.

Make a 10 to Add Practice 4.7

Make a 10 to add.

Question 1.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 111
Answer:

Sum as 6 + 4 + 1  = 11 or 6 + 5 = 11.

Explanation:
First we make sum 10, For 6 to make 10 we need 10-6=4,
as we have to add 4 to 6 now we will minus 4 from 5 we get 5 – 4 = 1,
Now we write the total sum as 6 + 4 + 1  = 11 or 6 + 5 = 11.

Question 2.
MP Number Sense
Use 2, 6, and 10 to complete the sentence.
________ + ________ has the same sum as ______ + 6.
Answer:

2 + 10   has the same sum as  6 + 6

Explanation:
Given to use numbers 2,6,10 to make the sentence
_______ +  _____ = ________ +  6 both sides sum is same
As right side 6 is given we substitute and check first we use 2, then 6 and 10,
2 +  6 = 8 now we have numbers 6 and 10, sum is 6 + 10 = 16
So (6 + 10) = 16  ≠ (2 + 6) = 8, next we take 6 and check 6 + 6 = 12
now we have numbers 2 , 10 and sum is 2 + 10 = 12
So (2 + 10) = 12 = ( 6 + 6) = 12 here if we take for 6 right side and 2,10 left
we get same sum both side, now we  even check taking 10 first,
10 + 6 = 16 in right side and we have numbers 2 and 6 for left as 2 + 6 =8,
So (2 + 6)= 8 ≠ (10 + 6) =16, So to make both the same sum
we take left side numbers as 2,10 and right side number 6
making the sentence as (2 + 10) = (6 + 6) = 12.

Question 3.
Modeling Real Life
There are 7 monkeys. 4 more join them. There are 6 birds. 5 more join them. Is the number of monkeys the same as the number of birds?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 112
Yes            No
Show how you know:
Answer:
Equations are:   Monkeys       Birds
7 + 4 = 11     6 + 5 = 11
Yes, the number of monkeys are the same as the number of birds.

Explanation:
Given 7 monkeys and 4 more joined them so total
monkeys are 7 + 4 = 11 and 6 birds, 5 more birds joined
making total as 6 + 5 = 11 birds as both are 11,
Yes, the number of monkeys are the same as the number of birds.

Review & Refresh

Question 4.
There are 3 Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113
2 more Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113 join them.
How many Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113 are there now?
____3____ + ___2____ = ____5____ Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 113
Answer:
3 + 2 = 5, there are 5 aero planes now.

Explanation:
Given there are 3 aero planes and 2 more join them making total
as 3 + 2 = 5 , therefore there are 5 aero planes now.

Question 5.
There are 4 Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114
6 more Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114 join them.
How many Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114 are there now?
___4_____ + ___6_____ = ___10_____ Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 114
Answer:
4 + 6 = 10, there are 10 airplanes now.

Explanation:
Given there are 4 aero planes and 6 more join them making total as  4 + 6 = 10, therefore there are 10 aero planes now.

Lesson 4.8 Problem Solving: Addition within 20

Explore and Grow

Newton has 9 red crayons, 3 blue crayons, and 1 yellow crayon. How many crayons does he have in all?

________ crayons
Answer:
Newton has 9 + 3 + 1 = 13 crayons in all.

Explanation:
Given Newton has 9 red crayons, 3 blue crayons and 1 yellow crayon,
So the total number of crayons Newton has are 9 + 3 + 1 = 13 crayons,
therefore Newton has 13 crayons in all.

Show and Grow

Question 1.
You have 6 notebooks. You buy 5 more. How many notebooks do you have now?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 115
Circle what you know.
Underline what you need to find.
Solve:

_______ ○ _______ = _______                           _______ notebooks
Answer:
notebooks
I have 11 notebooks in all.

Explanation:
Given I have 6 note books and buy 5 more , So I know
I have 6 & 5 books, So I circled what I know, I need to find
how many total notebooks I do have now, so I underlined it,
making 6 + 5 = 11 notebooks. So I have  total 11 notebooks now.

Apply and Grow: Practice

Question 2.
There are 6 soccer balls, 10 basketballs, and 4 volleyballs. How many balls are there in all?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 116
Circle what you know.
Underline what you need to find.
Solve:
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 117
Answer:
balls
I have 20 balls in all.

Explanation:
Given there are  6 soccer balls, 10 basketballs, and 4 volleyballs, So I know 6 , 10 & 4 balls, So I circled what I know, I need to find
how many total balls there in all so I underlined it, making 6 + 10 + 4 = 20 balls, therefore there are total 20 balls in all.

Question 3.
You do 8 push-ups. Your friend does I fewer than you. How many push-ups do you and your friend do in all?

____15_____ push-ups
Answer:
In total, I and my friend does 15 push-ups in all.

Explanation:
Given I do 8 push-ups and friend does 1 fewer than me
means 8-1 = 7 push-ups now total number of push-ups are
8 + 7 = 15, So in total I and my friend does 15 push-ups in all.

Question 4.
YOU BE THE TEACHER
Newton has 9 magnets. Descartes has 8 more than Newton. Your friend uses a bar model to show how many magnets Descartes has. Is your friend correct? Show how you know.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 118Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 118
Answer:
No, your friend is not correct as in bar model it is showing Descartes has 8 magnets.

Descartes has 9 + 8 =  17 magnets.
Explanation :
Given Newton has 9 magnets and Descartes has 8 more than Newton means Descartes has 9 + 8 = 17 magnets. But the bar model is showing Descartes has only 8 magnets, I have shown in the figure Descartes have 9 + 8 = 17 Magnets.

Think and Grow: Modeling Real Life

You have 5 bracelets. You have 7 fewer than your friend. How many bracelets does your friend have?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 119
Circle what you know.
Underline what you need to find.
Solve:
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 120

________ + ________ = _________                                       ____12____ bracelets
Answer:

Friend have 12 bracelets.

Explanation:
Given I have 5 bracelets, I have 7 fewer than my friend means
friend have in total as 5 + 7 = 12 bracelets, So circled what I know
5, 7 and underlined the number how many bracelets does friend have,
So friend have 12 bracelets.

Show and Grow

Question 5.
Your friend finds 9 seashells. You find 6 more than your friend. How many seashells do you find?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 121
Circle what you know.
Underline what you need to find.
Solve:

____6_____ + ___9____ = __15_____                                          ___15_____ seashells
Answer:

I found 15 seashells.

Explanation:
Given friend finds 9 seashells and I found 6 more than my friend,
So the total number of shells I found are 9 + 6 = 15 seashells.
I Know friend has 9 and I have more 6 seashells,
So I circled it and underlined to find how many seashells I found.

Problem Solving: Addition within 20 Practice 4.8

Question 1.
You have 5 robots. Your friend gives you more. Now you have 14. How many robots did your friend give you?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 122
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 123
Answer:

Friend has 9 robots.

Explanation :
Given I have 5 robots and now I have 14 robots so I circled it,
I need to find how many friend gives I have underlined it.
Let us take friend gives X robots and we write equation as
5 + X = 14, therefore X = 14 – 5 = 9 means friend gave 9 robots.

Question 2.
There are some plates on a table. You add 8 more. Now there are 12. How many plates were on the table to start?

______4____ plates
Answer:
There were 4 plates on the table to start.

Explanation:
Let us take X as some plates on the table, I added 8 more and
there are 12 now means X + 8 = 12, Therefore X = 12 – 8 = 4,
So 4 plates are there on the table to start.

Question 3.
YOU BE THE TEACHER
Newton has 8 tickets. Descartes has 5 more than Newton. Your friend uses a number line to show how many tickets Descartes has. Is your friend correct? Show how you know.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 124
Answer:
Descartes has 13 Tickets,
Yes, Friend is correct.

Explanation:
Given Newton has 8 tickets and Descartes has 5 more than Newton means 8 + 5 = 13 tickets, Descartes has 13  tickets, Now my friend is showing this on number line he is starting from 8 because Newton has 8 and moving 5 units to right as Descartes has 5 more tickets till 13
which is the same as we did sum 8 +5 = 13, So yes, friend is correct.

Question 4.
Modeling Real Life You have 9 medals. You have 9 fewer than your friend. How many medals does your friend have?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 125
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 126

____18_______ medals
Answer:

Friend have 18 medals.

Explanation:
Given I have 9 medals and 9 fewer than friend, So friend have
9 + 9 what I have, So friend have 18 medals.

Review & Refresh

Question 5.
4 – 3 = ________
Answer:
4- 3 = 1

Explanation:
Given the equation as 4 – 3 = _____ means subtract 3 from 4 we get 1
making equation as 4- 3 = 1.

Question 6.
5 – 2 = ________
Answer:
5 – 2 = 3

Explanation:
Given the equation as 5 – 2 = _____ means subtract 2 from 5 we get 3
making equation as 5 – 2 = 3.

Question 7.
9 – 9 = _________
Answer:
9 – 9 = 0

Explanation:
Given the equation as 9 – 9 = _____ means subtract 9 from 9 we get 0
making equation as 9 – 9 = 0.

Question 8.
7 – 0 = _________
Answer:
7 – 0 = 7

Explanation:
Given the equation as 7 – 0 = _____ means subtract 0 from 7 we get 7
making equation as 7- 0 = 7.

Add Numbers within 20 Performance Task

Question 1.
You track the weather for a few weeks. Each week has 7 days.
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 127

a. You track the weather every day for the first week. But you miss 1 day in the second week. How many days do you track the weather?

___13_______ days
Answer:
I have track of 13 days weather.

Explanation:
Given each week has 7 days, I have the track for every day for the first week,
Means the first week = 7 days, Now in the second week I missed 1 day means
7 – 1 = 6 days track in the second week, So the total number of days are
first week track + second week track = 7 + 6 = 13 , total I have track of 13 days weather.

b. You track the weather for 1 more week. How many days in all do you track the weather?

____20______ days
Answer:
I have track of 20 days weather in all.

Explanation :
Given that I have tracked for 1 more week, We got 13 days before
and now we have 1 more week means 7 days to 13 making total as
13 +  7 = 20 days, So now I have track of 20 days weather in all.

Question 2.
Your friend also tracks the weather. She records 9 sunny days and 5 cloudy days.
How many days does your friend track the weather?

____14______ days
Answer:
My friend has 14 days track record of the weather.

Explanation:
Given my friend records 9 sunny days and 5 cloudy days
track of the weather so in all my friend has track of
9 + 5 = 14 days. Therefore my friend has 14 days track record of the weather.

Question 3.
You record 10 rainy days in the first three weeks. Is the number of rainy days the same as the number of sunny days?
Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20 128
Yes                                No
Show how you know:
Answer:
No, Number of rainy days are not the same as the number of sunny days.

Explanation:
Given I record 10 rainy days in first three weeks and number of
sunny days for three weeks are 4 + 3 + 4 = 11 days , now comparing
with rainy days as rainy days are less to number of sunny days we say
No, number of rainy days are not the same as the number of sunny days.

Add Numbers within 20 Chapter Practice

Add Doubles from 6 to 10 Homework & Practice 4.1

Question 1.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 129
____10______ + ____10____ = ___20______
Answer:
10 + 10 = 20 dots

Explanation:
Given in block 1 we have 10 dots and in block 2 we have 10 dots,
So in total we have 10 + 10 = 20 dots.

Question 2.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 130
Answer:

9 + 9 = 18 dots

Explanation:
Given in block 1 we have 9 dots and in block 2 we have 9 dots,
So in total we have 9 + 9 = 18 dots.

Use Doubles within 20 Homework & Practice 4.2

Use the doubles 6 + 6 to find each sum.

Question 3.
6 + 7 = ___13_____
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 131
Answer:
6 + 7  = 13

Explanation:
We Know the double  6 + 6 = 12 , The number 7 is one more than 6,
So we can write 7 as 6 + 1, The required sum is one more than double,
12 + 1 =13, Sum is 13, therefore 6 + 7 = 13, Double plus 1.

6 + 5 = _______
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 132
Answer:
6 + 5 = 11

Explanation:
We Know the double of 6 + 6 = 12 , The number 5 is one less than 6,
So we can write 5 as 6 – 1, The required sum is one less than double,
12 – 1 = 11, Sum is 11, therefore 6 + 5 = 11, Double minus 1.

Find the sum. Write the double you used.

Question 4.
7 + 8 = _______

____7_____ ○ ____8____ = ___15____
Answer:

7 + 8 = 15, 7 + 7 double is used

Explanation:
As the first addend is 7 and we know the double of 7 + 7 = 14 ,
The number 8 is one more than 7, So we can write 8 as 7 + 1,
The required sum is one more than double,
14 + 1 =15, Sum is 15, therefore 7 + 8 = 15, we used the double 7 +7.

Question 5.
10 + 9 = ___19______

_________ ○ ________ = _______
Answer:
10 + 9 = 19, we use double 10 + 10,

Explanation:
As the first addend is 10 and we know the double is 10 + 10,
10 + 10 = 20 , The number 9 is one less than 10,
So we can write 9 as 10 – 1, The required sum is one less than double,
20 – 1 = 19, Sum is 19, therefore 10 + 9 = 17, Double minus 1.
We have use double 10 + 10 .

Count on to Add within 20 Homework & Practice 4.3

Question 6.
11 + 6 = ___17____
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 133
Answer:

11 + 6 = 17

Explanation:
First we start from 11 and move 6 units we get 17 on the number line,
So sum is 11 +6 = 17 .

Add Three Numbers Homework & Practice 4.4

Question 7.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 134
Answer:

6 + 4 + 4 = 14

Explanation:
By using linking the cubes
a. First we add 4 + 4 = 8 and now we add 6 + 8 we get 14.
b. Here we add 6 + 4 = 10, now we add 10 + 4 =14,
c. Now here we add first 6 with 4 we get 10 to 10 we add 4
we will get 10 + 4 = 14, So we get sum as 14.

Question 8.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 135
Answer:

7 + 8 + 5 = 20

Explanation:
By using linking the cubes
a. First we add 7 + 8 = 15 and now we add 15+ 5 we get 20.
b. Here we add 8 + 5 = 13, now we add 13 + 7 =20,
c. Now here we add first 7 with 5 we get 12 to 12 we add 8
we will get 12 + 8 = 20, So we get sum as 20.

Question 9.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 136
Answer:

9 + 8 + 1 = 18

Explanation:
By using linking the cubes
a. First we add 9 + 8 = 17 and now we add 17 + 1 we get 18.
b. Here we add 8 + 1 =9, now we add 9 + 9 =18,
c. Now here we add first 9 with 1 we get 10 to 10 we add 8
we will get 10 + 8 = 18, So we get sum as 18.

Question 10.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 137
Answer:

2 + 3 + 5 = 10

Explanation:
By using linking the cubes
a. First we add 2 + 3 = 5 and now we add 5 + 5 we get 10.
b. Here we add 3 + 5 =8, now we add 8 + 2 =10,
c. Now here we add first 2 with 5 we get 7 to 7 we add 3
we will get 7 + 3 = 10, So we get sum as 10.

Add Three Numbers by Making a 10 Homework & Practice 4.5

Make a 10 to add.

Question 11.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 138
Answer:

Add 7,3 first to make 10 then add 9, sum = 7 + 9 + 3 = 19

Explanation:
To make 10 first we see adding 7 + 9 = 16 is not equal to 10,
next we add 9 + 3 = 12 not equal to 10, 7 + 3 = 10 which
is equal to 10 ,So to make 10 we add  7,3 first, then add 9,
So the sum is 7 + 9 + 3 = 19.

Question 12.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 139
Answer:

Add 9,1 first to make 10 then add 4, sum = 4 + 9 + 1 = 14

Explanation:
To make 10 first we see adding 4 + 9 = 13 is not equal to 10,
next we add 9 + 1 = 10 is equal to 10, 4 + 1 = 5 which
is not equal to 10 ,So to make 10 we add  9,1 first, then add 4,
So the sum is 4 + 9 + 1 = 14.

Question 13.
MP Number Sense
What do you know about the missing addends and the sum?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 140
Answer:
We know the sum of the missing addends is 10 and the total sum is 10 + 5 = 15.

Explanation:
From the picture it is showing that if we add the missing
addends we get sum as 10 and the total sum is 10 + 5 = 15.
So whenever we are adding two missing addends we should always check,
their sum should be always 10, Example if one number is 1
other number will be 10-1 = 9. So the missing numbers are (1,9).
It can be even (2,8), (3,7),(4,6),(5,5),(6,4),(7,3),(8,2) or (9,1).

Add 9 Homework & Practice 4.6

Question 14.
Make a 10 to add 9 + 4.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 141
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 142
Answer:

Sum as 9 + 1 + 3 = 13  or 9 + 4 = 13.

Explanation:
First we make sum 10 , For 9 to make 10 we need 10-9=1,
as we have to  add 1 to 9 now  we will minus 1 from 4 we get 4 – 1 = 3,
Now we write the total sum as 9 + 1 + 3 = 13  or 9 + 4 = 13.

Make a 10 to Add Homework & Practice 4.7

Question 15.
Make a 10 to add 8 + 5.
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 143
Answer:

Sum as 8 + 2 + 3 = 13  or 8 + 5 = 13.

Explanation:
First we make sum 10 , For 8 to make 10 we need 10-8=2,
as we have to  add 2 to 8 now  we will minus 2 from 5 we get 5 – 2 = 3,
Now we write the total sum as 8 + 2 + 3 = 13  or 8 + 5 = 13.

Question 16.
7 + 7 = ?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 144
Answer:

Sum as 7 + 3 + 4  = 14 or 7 + 7 = 14.

Explanation:
First we make sum 10, For 7 to make 10 we need 10-7=3,
as we have to add 3 to 7 now we will minus 3 from 7 we get 7 – 3 = 4,
Now we write the total sum as 7 + 3 + 4  = 14 or 7 + 7 = 14.

Question 17.
9 + 8 = ?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 145
Answer:

Sum as 9 + 1 + 7  = 17 or 9 + 8 = 17.

Explanation:
First we make sum 10, For 9 to make 10 we need 10-9=1,
as we have to add 1 to 9 now we will minus 1 from 8 we get 8 – 1 = 7,
Now we write the total sum as 9 + 1 + 7  = 17 or 9 + 8 = 17.

Problem Solving: Addition within 20 Homework & Practice 4.8

Question 18.
Modeling Real Life
Your friend finds 7 insects. You find 9 more than your friend. How many insects do you find?
Big Ideas Math Solutions Grade 1 Chapter 4 Add Numbers within 20 146

_____16____ insects
Answer:
I found 16 insects.

Explanation:
Given a friend finds 7 insects, I find 9 more than my friend means
I have in total as 7 + 9 = 16 insects,
So I found 16 insects.

Conclusion:

Learn the Big Ideas Math Book 1st Grade Answer Key Chapter 4 Add Numbers within 20 provided and improve your math as well as problem solving skills. You can achieve greater heights and fall in love with Math with our Big Ideas Math Answers Grade 1 Chapter 4 Add Numbers within 20. Stay with us to get the solutions of all Big Ideas Math Grade 1 Chapters from 1 to 14.

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