Practice with the help of enVision Math Common Core Grade 1 Answer Key **Topic 11 Use Models and Strategies to Subtract Tens** regularly and improve your accuracy in solving questions.

## enVision Math Common Core 1st Grade Answers Key Topic 11 Use Models and Strategies to Subtract Tens

**enVision STEM Project: Tools Solve Problems**

**Find Out** Talk to friends and relatives about different tools we use to solve problems. Ask them about tools they use in their everyday lives.

**Journal: Make a Book** Show what you found out. In your book, also:

- Draw some tools that solve simple problems. Make sure to describe the simple problems they solve.
- Make up and solve subtraction problems about tools.

**Review What You Know**

**Vocabulary**

Question 1.

How many tens are in this number?

23

__ tens

Answer:

2 tens .

Explanation :

23 have 2 is in tens place and 3 is in Ones place .

Question 2.

Use the hundred chart to count by 10s.

30, 40, 50, ___, ___

Answer:

30, 40, 50, 60, 70 .

Question 3.

Use the open number line to add.

7 + 9 = __

Answer:

Explanation :

Start at 7 and to add 9 make 9 jumps from 7 you land at 16 which is the sum .

**Count Back to Subtract**

Question 4.

Mark takes 8 pictures. Julia takes 3 fewer pictures than Mark. Count back to find how many pictures Julia took.

8, __, ___, __ __ pictures

Answer:

Number of Pictures taken by Mark = 8

Number of pictures taken by Julia = 3 fewer pictures than Mark = 8 – 3 = 5 Pictures .

Explanation :

Start at 8 and to subtract 3 from 8 . jump back 3 times you will land at 5 which is the difference .

Question 5.

Katie picks 15 flowers. Max picks 13 flowers. Count back to find how many fewer flowers Max picked than Katie.

15, ___, ___ ___ fewer flowers

Answer:

Number of Flowers Katie picks = 15 flowers

Number of flowers Max picks = 13 flowers

Number of fewer flowers Max picked than Katie = 15 – 13 = 2 flowers .

Therefore, Number of fewer flowers Max picked than Katie = 2 flowersÂ .

Explanation :

Count back

Start at 15 and count back and make 13 jumps as we are subtracting 13 .

you land at 2 , which is the difference .

**Subtraction Facts**

Question 6.

Find each difference.

12 – 4 = ___

14 – 7 = ___

19 – 9 = ___

Answer:

12 – 4 = 8

14 – 7 = 7

19 – 9 =10

**Pick a Project**

**PROJECT 11A**

Have you ever looked closely at money?

Project: Study Penny Collections

**PROJECT 11B**

Where are baby sea turtles born?

Project: Tell Sea Turtle Subtraction Stories

**PROJECT 11C**

What’s your favorite flavor of smoothie?

Project: Set Up a Smoothie Stand

**3-ACT MATH PREVIEW**

**Math Modeling**

**So Many Colors**

Before watching the video, think: When you clean up, how many toys can you clean up at the same time? How can you tell how many toys fit in a container?

### Lesson 11.1 Subtract Tens Using Models

**Solve & Share**

How can thinking about 4 â€“ 1 help you to find 40 â€“ 10? Use place-value blocks to help you.

Answer :

**Visual Learning Bridge**

**Convince Me!**

When you solve 40 â€“ 10, how does the tens digit change? How does the ones digit change?

Answer :

40 – 10 = 30

In tens digit only the tens values are subtracted and the ones digit will remain same as 0 .

In Ones digit only the subtracted values are written .

**Guided Practice**

Write the numbers to complete each equation.

Question 1.

Answer:

Explanation :

70 – 10 is like subtracting 1 ten from groups of 10 .

7 tens – 1 tens = 6 tens .

Question 2.

___ tens – ___ tens = ___ tens.

__ – __ = ___

Answer:

Explanation :

60 – 20 is like subtracting 1 ten from groups of 10 .

6 tens – 2 tens = 4 tens .

**Independent Practice**

Write the numbers to complete each equation.

Question 3.

___ tens – ___ tens = ___ tens.

__ – __ = ___

Answer:

Explanation :

80 – 30 is like subtracting 1 ten from groups of 10 .

8 tens – 3 tens = 5 tens .

Question 4.

___ tens – ___ tens = ___ tens.

__ – __ = ___

Answer:

Explanation :

50 – 10 is like subtracting 1 ten from groups of 10 .

5 tens – 1 tens = 4 tens .

Question 5.

___ tens – ___ tens = ___ tens.

__ – __ = ___

Answer:

Explanation :

80 – 20 is like subtracting 1 ten from groups of 10 .

8 tens – 2 tens = 6 tens .

Question 6.

___ tens – ___ tens = ___ tens.

__ – __ = ___

Answer :

Explanation :

60 – 30 is like subtracting 1 ten from groups of 10 .

6 tens – 3 tens = 3 tens .

**Problem Solving**

Solve each problem below.

Question 7.

Ethan has 30 crayons. He gives 10 crayons away. How many crayons does Ethan have now? Write the equation.

__ – ___ = ____ crayons

Answer :

Number of Crayons with Ethan = 30 crayons

Number of Crayons given away = 10 crayons .

Number of crayons with Ethan now = 30 – 10 = 20 crayons .

Question 8.

Algebra Jacob solved these problems. Did Jacob subtract 1 or 10?

Finish the equations.

50 – = 40

60 – = 59

Answer:

so, Jacob used both 10 and 1 to subtract the equations .

Explanation :

To get 40 as difference we need to subtract 10 from 50 .

To get 59 as difference we need to subtract 1 from 60 .

Question 9.

**Higher Order Thinking** Write and solve a story problem for 90 – 10.

Answer:

Question 10.

**Assessment Practice** 20 teddy bears are for sale at the store. Then, 10 teddy bears are sold.

How many teddy bears are on sale at the store now?

Answer:

Option c – 10

Explanation :

Number of teddy bears for sale = 20

Number of teddy bears are sold = 10

Number of teddy bears are left = 20 – 10 = 10 bears .

### Lesson 11.2 Subtract Tens Using a Hundred Chart

**Solve & Share**

Use a hundred chart to find these differences. 50 â€“ 30 = ? 30 â€“ 20 = ? 80 – 10 = ? Explain.

Answer :

**Visual Learning Bridge**

**Convince Me!**

Find 80 – 50. Explain how you found the difference.

Answer :

Explanation :

Start at 80

For every ten we subtract, move up 1 row – to subtract 50 that is 5 tens we move up 5 rows .

after moving 5 rows we land at 30 which is the difference .

**Guided Practice**

Use the chart to subtract. Be ready to explain your work.

Question 1.

40 – 10 = __30
Answer :
__

Question 2.

40 – 20 = __

Answer:

Question 3.

30 – 20 = ___

Answer:

Question 4.

10 â€“ 10 = ___

Answer:

10 â€“ 10 = 0

Explanation :

start at 10

To subtract 10 from 10

cancel 10 numbers from 10 count back

it will land at 0 , the difference .

**Independent Practice**

Use the chart to subtract. Be ready to explain your work.

Question 5.

50 â€“ 30 = ___

Answer:

Question 6.

80 â€“ 60 = ___

Answer:

Question 7.

30 – 30 = ___

Answer:

Question 8.

90 – 30 = ___

Answer:

Question 9.

70 â€“ 20 = ___

Answer:

Question 10.

20 â€“ 10 = ___

Answer:

Question 11.

60 â€“ 30 = ___

Answer:

Question 12.

90 â€“ 50 = ___

Answer:

Question 13.

90 â€“ 40 = ___

Answer:

Question 14.

80 â€“ 40 = ___

Answer :

Algebra Find the missing numbers.

Question 15.

30 – ___ = 20

Answer:

30 – ___ = 20

30 – 20 = x

x = 10 .

Question 16.

___ – 30 = 10

Answer:

40

Explanation :

___ – 30 = 10

x – 30 = 10

x = 30 + 10

x = 40 .

Question 17.

___ – 50 = 20

Answer:

70

Explanation :

___ – 50 = 20

x – 50 = 20

x = 50 + 20

x = 70 .

Question 18.

20 â€“ ___ = 0

Answer :

20

Explanation :

20 â€“ ___ = 0

20 â€“ x = 0

x = 20 .

Question 19.

___ – 20 = 30

Answer:

50

Explanation :

___ – 20 = 30

x – 20 = 30

x = 30 + 20

x = 50 .

Question 20.

70 – __ = 30

Answer:

40

Explanation :

70 – __ = 30

70 – x = 30

x = 70 -30

x = 40 .

**Problem Solving**

Use the chart to solve each problem. Show your work.

Question 21.

**Use Tools** Colvin throws a dart at a target 70 times. 10 times, he misses the target. How many times did he hit the target?

__ – ___ = ___

___ times

Answer:

Number of times he threw the dart = 70 times.

Number of times he misses the target = 10 times .

Number of times he targets = 70 – 10 = 60 times .

Question 22.

**Use Tools** Mal’s basketball team scores 40 points. They score 10 more points than the other team. How many points did the other team score?

__ – ___ = ___

___ points

Answer:

Score of Mal’s basketball team = 40 points .

Score of other team = 10 more points than the other team = 40 – 10 = 30 points .

Question 23.

**Higher Order Thinking** Circle any number in the last row of the partial hundred chart above. Subtract 30. Write your equation.

Answer:

Any number of last row of the partial hundred chart above = 70 .

70 – 30 = 40

Question 24.

**Assessment Practice** Leo makes 50 muffins for his class bake sale. He sells 10 muffins. How many muffins are left?

A. 10

B. 20

C. 30

D. 40

Answer:

Number of muffins baked = 50

Number of muffins for sold = 10

Number of muffins left = 50 – 10 = 40 . muffins .

Therefore, Number of muffins left = 40 muffins .

### Lesson 11.3 Subtract Tens Using an Open Number Line

**Solve & Share**

Solve 50 â€“ 20 by showing it on this open number line. Be ready to explain your work.

Answer :

**Visual Learning Bridge**

**Convince Me!**

How can you use an open number line to subtract tens?

Answer :

We can use open number line for subtraction by counting back .

**Guided Practice**

Use the open number line to subtract. Be ready to explain your work.

Question 1.

30 – 20 = ___

Answer:

30 – 20 = 10 .

Explanation :

Start at 30 . Use place value take 20 as 2 groups of 10 .

count back 2 10’s from 30 .

we land on 10 which is the difference .

Question 2.

90 – 50 = ___

Answer:

Explanation :

Start at 90 . Use place value take 50 as 5 groups of 10 .

count back 5 10’s from 90 .

we land on 40 which is the difference .

**Independent Practice**

Use the open number lines to subtract. Be ready to explain your work.

Question 3.

70 â€“ 20 = ___

Answer:

Explanation :

Start at 70 . Use place value take 20 as 2 groups of 10 .

count back 2 10’s from 70 .

we land on 50 which is the difference .

Question 4.

60 â€“ 10 = __

Answer:

Explanation :

Start at 60 . Use place value take 10 as 1 group of 10 .

count back 1 10’s from 60 .

we land on 50 which is the difference .

Question 5.

80 â€“ 30 = __

Answer:

Explanation :

Start at 80 . Use place value take 30 as 3 groups of 10 .

count back 3 10’s from 80 .

we land on 50 which is the difference .

Question 6.

40 â€“ 40 = ___

Answer:

Explanation :

Start at 40 . Use place value take 40 as 4 groups of 10 .

count back 4 10’s from 40 .

we land on 0 which is the difference .

**Problem Solving**

Use open number lines to solve the problems.

Question 7.

Model Dexter has 40 toothpicks. He uses 20 of them. How many toothpicks does he have left to use? Show your work.

___ – ___ = ___ Dexter has ___ toothpicks left.

Answer:

Total Number of tooth picks = 40

Number of tooth picks used = 20 .

Number of tooth picks left = 40 – 20 = 20Â tooth picks .

Question 8.

**Higher Order Thinking** Write an equation for what this number line shows.

Answer:

50 – 30 = 20 .

Explanation :

started at 50 .

each jump represent – 10 .

3 jumps are made from 50 that is -30 .

lands on 20 which is the difference .

Question 9.

**Assessment Practice** Find 80 â€“ 20. Explain your work.

Answer:

Explanation :

Start at 80 . Use place value take 20 as 2 groups of 10 .

count back 2 10’s from 80 .

we land on 60 which is the difference .

### Lesson 1.4 Use Addition to Subtract Tens

**Solve & Share**

Mia has 70 stickers. Jack has 30 stickers. How many more stickers does Mia have than Jack has?

Answer :

**Visual Learning Bridge**

**Convince Me!**

How can using addition help you solve subtraction problems?

Answer :

WithÂ addition, the parts are known, but not the total; withÂ subtraction, the total and one of the parts are known, but not the other part. Because of this relationship between the two operations,Â using additionÂ is the most effective thinking strategy forÂ helpingÂ students learn the basicÂ subtraction facts .

**Guided Practice**

Use addition to solve each subtraction problem. Show how to find the missing addend on the open number line.

Question 1.

Answer:

Explanation :

Each jump represent + 10, 4 jumps are made 40 is added .

Start at 40 and make 4 jumps . You land on 80 , which is the sum .

From 80 , if we Subtract 40,we get 40 as difference.

Question 2.

30 + ___ = 90 so 90 – 30 = __

Answer:

Explanation :

Each jump represent + 10, 6 jumps are made 60 is added .

Start at 30 and make 6 jumps . You land on 90 , which is the sum .

From 90 , if we Subtract 30, we get 60 as difference .

**Independent Practice**

Use addition to solve each subtraction problem. Show how to find the missing addend on the open number line.

Question 3.

20+ ___ = 60, so 60 â€“ 20 = ___

Answer:

Explanation :

Each jump represent + 10, 4 jumps are made 40 is added .

Start at 20 and make 4 jumps . You land on 60 , which is the sum .

From 60 , if we Subtract 20, we get 40 as difference .

Question 4.

30 + ___ = 80, so 80 – 30 = ___

Answer :

Explanation :

Each jump represent + 10, 5 jumps are made 50 is added .

Start at 30 and make 5 jumps . You land on 80 , which is the sum .

From 80 , if we subtract 30, we get 50 as difference .

Use addition to solve each subtraction problem. Draw a picture to show your thinking.

Question 5.

30 + ___ = 50, so 50 – 30 = ___

Answer :

Explanation :

Each jump represent + 10, 2 jumps are made 20 is added .

Start at 30 and make 2 jumps . You land on 50 , which is the sum .

From 50 , if we subtract 30, we get 20 as difference .

Question 6.

60 + __ = 80, so 80 â€“ 60 = ___

Answer:

Explanation :

Each jump represent + 10, 2 jumps are made 20 is added .

Start at 60 and make 2 jumps . You land on 80 , which is the sum .

From 80 , if we subtract 60, we get 20 as difference .

**Problem Solving**

Write an equation and solve the problems below.

Question 7.

**Reasoning** Mr. Andrews collects 90 papers from his students. He has already graded 40 papers. How many papers does Mr. Andrews have left to grade?

__ papers

Answer:

Number of papers collected by Mr. Andrew = 90 papers

Number of papers graded = 40 papers .

Number of papers left to grade = 90 – 40 = 50 papers .

Therefore, Number of papers left to grade = 50 papersÂ .

Question 8.

**Reasoning** Stacy drives 40 miles to work. She has already driven some miles. Stacy has 20 miles left to drive. How many miles has Stacy already driven?

___ miles

Answer:

Number of miles Stacy drives = 40 miles .

Number of miles left to drive = 20 miles.

Number of miles driven by Stacy = 40 – 20 = 20 miles .

Therefore, Number of miles driven by Stacy = 20 miles .

Question 9.

**Higher Order Thinking** Sam has 4 cases of juice boxes. There are 10 juice boxes in each case. He brings 3 cases to share with his class.

Write and solve an equation to show how many juice boxes Sam has left.

__ – __ = ___

___ juice boxes

Answer:

Number of cases of juice boxes = 4

Number of juice boxes in each case = 10 .

Number of cases of juice boxes Sam took to share = 3

Number of cases of juice boxes left = 4 – 3 = 1 case .

Number of juice boxes in 1 case = 10 .juice boxes .

Therefore, Number of juice boxes left = 10 juice boxes .

Question 10.

**Assessment Practice** Dr. Tess had 20 patients to see today. She has already seen 10 of them. How many patients does Dr. Tess have left to see?

A 40

B 30

C 20

D 10

Answer:

Option D – 10 .

Explanation :

Number of patients = 20 .

Number of patients already seen by Dr . = 10 .

Number of patients left to see = 20 – 10 = 10 patients .

### Lesson 11.5 Mental Math: Ten Less Than a Number

**Solve & Share**

Suppose you have 89 trading cards. How many cards would 10 more cards be? How many cards would 10 less cards be?

Answer :

89 + 10 = 99

tens digit value is increased by 1, 8tens + 1 tens = 9 tens

ones digit value remains same . 9 ones .

89 – 10 = 79

tens digit value is decreased by 1, 8tens – 1 tens = 7 tens

ones digit value remains same . 9 ones .

Explanation :

Adding 10 increasesÂ the theÂ digit in the tens placeÂ by 1 (as long as it is not 9).

Subtracting 1 decreases the theÂ digit in the tens placeÂ by 1 (as long as it is not 0).

**Visual Learning Bridge**

**Convince Me!**

Explain why only the tens digit changes when you subtract 10 from 76.

Answer :

Subtracting 10 from the 76 decreases one from the tens digit value

that is 7 – 1 = 6

and ones digit 6 remains the same as any number subtracted from 0 gives number itself .

so, no change takes place to the one’s digit value .

so, 76 – 10 = 66 .

**Guided Practice**

Use mental math to subtract. Use ten-frames if needed.

Question 1.

Answer:

Explanation :

26 is represented in ten frame .

to subtract 10 from 26 complete 1 ten frame is removed

then difference = 16 .

Question 2.

32 – 10 = ___

Answer:

Explanation :

32 is represented in ten frame .

to subtract 10 from 32 complete 1 ten frame is removed

then difference = 22 .

Question 3.

98 – 10 = ___

Answer:

Explanation :

98 is represented in ten frame .

to subtract 10 from 98 complete 1 ten frame is removed

then difference = 88 .

Question 4.

44 – 10 = __

Answer:

Explanation :

44 is represented in ten frame .

to subtract 10 from 44 complete 1 ten frame is removed

then difference = 34 .

**Independent Practice**

Use mental math to solve.

Question 5.

53 â€“ 10 = ___

Answer:

Explanation :

53 is represented in ten frame .

to subtract 10 from 53 complete 1 ten frame is removed

then difference = 43 .

Question 6.

20 â€“ 10 = __

Answer:

Explanation :

20 is represented in ten frame .

to subtract 10 from 20 complete 1 ten frame is removed

then difference = 10 .

Question 7.

32 â€“ 10 = ___

Answer:

Explanation :

32 is represented in ten frame .

to subtract 10 from 32 complete 1 ten frame is removed

then difference = 22 .

Question 8.

80 â€“ 10 = __

Answer:

Explanation :

80 is represented in ten frame .

to subtract 10 from 80 complete 1 ten frame is removed

then difference = 70 .

Question 9.

17 â€“ 10 = ___

Answer:

Explanation :

17 is represented in ten frame .

to subtract 10 from 17 complete 1 ten frame is removed

then difference = 7 .

Question 10.

60 â€“ 10 = ___

Answer:

Explanation :

60 is represented in ten frame .

to subtract 10 from 60 complete 1 ten frame is removed

then difference = 50 .

Question 11.

47 â€“ 10 = ___

Answer:

Explanation :

47 is represented in ten frame .

to subtract 10 from 47 complete 1 ten frame is removed

then difference = 37 .

Question 12.

85 â€“ 10 = ___

Answer:

Explanation :

85 is represented in ten frame .

to subtract 10 from 85 complete 1 ten frame is removed

then difference = 75 .

Question 13.

11 – 10 = ___

Answer:

Explanation :

11 is represented in ten frame .

to subtract 10 from 11 complete 1 ten frame is removed

then difference = 34 .

Question 14.

**Number Sense** Subtract using ten-frames and mental math. Complete the related addition equation.

Answer:

Explanation :

39 is represented in ten frame .

to subtract 10 from 39 complete 1 ten frame is removed

then difference = 29.

**Problem Solving**

Use mental math to solve the problems below.

Question 15.

**Reasoning** Jamal has 43 stamps on his desk. He puts 10 stamps in a notebook. How many stamps are left?

__ stamps

Answer:

Explanation :

Number of stamps on desk = 43 stamps.

Number of stamps kept in book = 10 stamps.

Number of stamps left over = 43 – 10 stamps = 33 stamps.

Question 16.

**Vocabulary** Ed brings 27 oranges home. His family eats 10 of them. How many oranges does Ed have left? Find the difference.

27 – 10 = ___

___ oranges

Answer:

Number of Oranges brought = 27

Number of Oranges family ate = 10

Number of oranges left = 27 – 10 = 17

Therefore, Number of oranges left = 17 oranges .

Question 17.

**Higher Order Thinking** Write a subtraction story about 56 â€“ 10. Then solve your story.

Answer:

Addy have 56 mangos to sell . he sold 10 mangos, How many mangos did Addy left with ?

Answer :

Total Number of Mangoes = 56

Number of Mangoes sold = 10 .

Number of mangoes left = 56 – 10 = 46 mangoes .

Question 18.

**Assessment Practice** Use mental math to find 44 – 10.

A 54

B 45

C 43

D 34

Answer:

Option D – 34.

Explanation :

Subtracting 10 from the 44 decreases one from the tens digit value

that is 4 – 1 = 3

and ones digit 4 remains the same as any number subtracted from 0 gives number itself .

so, no change takes place to the one’s digit value .

so, 44 – 10 = 34 .

### Lesson 11.6 Use Strategies to Practice Subtraction

**Solve & Share**

Make up a story about 60 â€“ 40. Then solve the subtraction problem. Use the strategy you think works best.

Answer :

**Visual Learning Bridge**

**Convince Me!**

Which strategy would you use to solve 50 â€“ 40? Explain why.

Answer :

Number line.

Explanation :

Each jump represent -10 .

Start at 50 and make 4 jumps that is – 40 .

it lands on 10 which is the difference .

**Guided Practice**

Use the partial hundred chart or another strategy to solve each subtraction problem.

Question 1.

70 â€“ 10 = __60__

Answer:

Question 2.

60 â€“ 20 = __

Answer:

Question 3.

43 â€“ 10 = ___

Answer:

Question 4.

70 â€“ 30 = __

Answer:

**Independent Practice**

Use the strategy you think works best to solve each subtraction problem. Explain your reasoning.

Question 5.

90 â€“ 40 = ___

Answer :

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

Question 6.

40 – 20 = ___

Answer:

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

Question 7.

80 â€“ 60 = ___

Answer:

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

Question 8.

50 – 20 = ___

Answer:

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

Question 9.

74 – 10 = ___

Answer:

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

Question 10.

80 â€“ 40 = ___

Answer:

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

Question 11.

**enVisionÂ® STEM** Students at a school plant flowers in a garden. They plant 50 flowers in a part that gets a lot of sunshine. They plant 30 flowers in a part that is shaded from the sun. How many fewer flowers did they plant in a shaded spot than in a sunny spot? Write an equation to show your work.

___ – ___ = ___ ___ fewer flowers

Answer :

Number of flower plants planted in sunshine = 50 flowers .

Number of flower plants planted in sunny spot = 30 flowers .

Number of fewer flower plants planted in shaded spot than in a sunny spot = 50 – 30 = 20 fewer flowers .

Therefore, 20 fewer flower plants are planted in shaded spot than in a sunny spot .

**Problem Solving**

Choose one of the strategies you learned to solve each subtraction problem.

Question 12.

**Use Tools** Charlie puts baseball cards into an album. He already put 10 cards in the album. He has 83 cards in all.

How many baseball cards does Charlie have left to put in the album?

__ cards

Answer:

Total Number of cards = 83 cards .

Number of cards kept in album = 10 cards .

Total number of cards left to put in album = 83 – 10 = 73 cards .

Explanation :

Question 13.

**Use Tools** Pearl’s basketball team scores 50 points in one game. They score some points in the first half. They score 20 points in the second half.

How many points did Pearl’s team score in the first half?

___ points

Answer:

Number of points scored by pearl’s team = 50 points .

Number of points in second half = 20

Number of points scored in first half = 50 – 20 = 30 points .

Explanation :

Question 14.

**Higher Order Thinking** Write a subtraction problem for which you would think addition to subtract. Explain why this would be a good strategy to use to solve this problem.

Answer:

Andy walks 80 miles from his house to school to park . heÂ walks 60 miles from school to park . How many miles did he walk from house to school?

Solution :

Number of miles andy walk = 80 miles.

Number of miles he walked from School to park = 60 miles.

Number of miles he walked from house to school = 80 – 60 = 20 .

Explanation :

Each jump represent + 10, 2 jumps are made 20 is added .

Start at 60 and make 2 jumps . You land on 80 , which is the sum .

From 80 , if we subtract 60, we get 20 as difference .

Question 15.

**Assessment Practice** Explain how you would use a hundred chart to solve 60 â€“ 20.

Answer:

### Lesson 11.7 Model with Math

**Solve & Share**

Val picks 40 strawberries. She shares 20 of them with her brother. How many strawberries did Val keep for herself?

How can modeling your thinking help you solve this problem?

Answer :

**Thinking Habits**

Can I use a drawing, diagram, graph, or table to model this problem? How can I make my model better if it doesn’t work?

**Visual Learning Bridge**

**Convince Me!**

In the example above, how do the boxes of 10 help model the problem?

Answer :

The sum is given in the multiples of ten so, each box represent 10 and 70 is represented as 7 boxes to subtract 40 we need to cancel 4 boxes .

it made calculation part easier and simple .

**Guided Practice**

Use drawings, models, or equations to solve.

Question 1.

A store has 60 muffins. It sells 30 of the muffins. How many muffins does the store have now?

__30__ muffins

Answer:

Number of muffins at store = 60 muffins .

Number of muffins sold = 30 muffins .

Number of muffins left out = 60 – 30 = 30 muffins .

Therefore, Number of muffins left out = 30 muffins .

Question 2.

Andy has 84 baseball cards. He has 10 more cards than Tia has. How many cards does Tia have?

___ cards

Answer:

Number of base ball cards with Andy = 84 .

Andy has 10 more cards than Tia that means Tia have 10 less cards than Andy

Number of base ball cards with Tia = 84 – 10 = 74 cards .

**Independent Practice**

Use drawings, models, or equations to solve. Explain your work.

Question 3.

Viola has 80 stickers. Dean has 60 stickers. How many more stickers does Viola have than Dean?

___ more stickers

Answer:

Number of Stickers with Viola = 80 stickers.

Number of stickers with Dean = 60 stickers .

Number of More stickers Viola have than Dean – 80 – 60 = 20 stickers .

Explanation :

Question 4.

Carla reads some pages in a book. She reads 20 pages less than Mary reads. Mary reads 50 pages. How many pages did Carla read?

__ pages

Answer:

Number of pages Read by Mary = 50 pages .

Carla reads 20 pages less than Mary reads

Number of pages read by Carla = 50 – 20 = 30 pages .

Question 5.

A store has 72 toy cars. It sells 10 cars. How many cars does the store have left?

___ cars

Answer:

Number of car toys = 72 .

Number of car toys sold = 10 .

Number of car toys left = 72 – 10 = 62 toys .

Therefore, Number of car toys left = 62 toys .

**Problem Solving**

**Performance Task**

**Dog Walking** James, Emily, and Simon walk dogs after school.

On Monday, they have 40 dogs to walk. James and Emily take 20 of the dogs for a walk. How many dogs are left for Simon to walk?

Answer:

Total Number of dogs = 40 dogs

Number of dogs James and Emily took for walking = 20 dogs .

Number of dogs left to take for walking by Simon = 40 – 20 = 20 dogs .

Therefore, Simon takes 20 dogs for walk .

Question 6.

**Make Sense** What problem do you need to solve?

Answer:

Number of dogs left to take for walking by Simon .

Question 7.

**Use Tools** What tool or tools can you use to solve this problem?

Answer:

Subtraction

Question 8.

**Model** Write an equation to show the problem. Then use pictures, words, or symbols to solve.

___ dogs

Answer:

Number of dogs left to take for walking by Simon = 40 – 20 = 20 dogs .

### Topic 11 Fluency Practice Activity

**Point & Tally**

Find a partner. Get paper and a pencil. Each partner chooses a different color: light blue or dark blue.

Partner I and Partner 2 each point to a black number at the same time. Subtract Partner 2’s number from Partner 1’s number.

If the answer is on your color, you get a tally mark. Work until one partner gets twelve tally marks.

**Topic Vocabulary Review**

**Understand Vocabulary**

Question 1.

Subtract the tens shown by the model.

__ tens – __ tens = ___ tens

Answer:

Explanation :

60 – 30 is like subtracting 1 ten from groups of 10 .

6 tens – 3 tens = 3 tens .

Question 2.

Subtract the tens shown by the model.

__ tens – __ tens = ___ tens

Answer:

Explanation :

80 – 60 is like subtracting 1 ten from groups of 10 .

8 tens – 6 tens = 2 tens .

Question 3.

Circle the addition problem that could help you solve 50 â€“ 30.

10 + 40 = 50

25 + 25 = 50

30 + 20 = 50

40 + 10 = 50

Answer:

Explanation :

50 – 30 = 20

20 + 30 = 50 .

Question 4.

Solve 40 â€“ 20 using a partial hundred chart. Circle the difference.

Answer:

Question 5.

Use mental math to solve 70 â€“ 10. Circle the difference.

Answer:

70 – 10 = 60

Explanation :

70 is represented in ten frame .

to subtract 10 from 70 complete 1 ten frame is removed

then difference = 60 .

**Use Vocabulary in Writing**

Question 6.

Solve 80 – 50 using an open number line. Explain how you solved it using terms from the Word List.

Answer:

Explanation :

Each jump represent – 10, 5 jumps are made that is -50 . .

Start at 80 and make 5 jumps . You land on 30 , which is the difference count back .

### Topic 11 Reteaching

**Set A**

You can subtract tens.

40 â€“ 30 = __?__

You need to subtract 30, which is 3 tens.

Cross out that many tens.

Count the tens and ones that are left.

40 – 30 = 10

Cross out the tens. Write the difference.

Question 1.

60 â€“ 40 = ___

Answer:

Explanation :

You need to subtract 40, which is 4 tens.

Cross out 4 tens.

Count the tens and ones that are left are 20 which is the difference .

60 – 40 = 20

Question 2.

50 – 20 = ___

Answer:

Explanation :

You need to subtract 20, which is 2 tens.

Cross out 2 tens.

Count the tens and ones that are left are 30 which is the difference .

50 – 20 = 30

**Set B**

You can use a hundred chart to subtract tens.

80 – 20 = __?__

Use this partial hundred chart to subtract tens.

Question 3.

70 â€“ 20 = ___

Answer:

Explanation :

Start at 70 .

For every 10 you subtract , move up 1 row .

20 , is 2 tens . so, move up 2 rows .

lands on 50 which is the difference .

Question 4.

60 â€“ 10 = ___

Answer:

60 â€“ 10 = 50 .

Explanation :

Start at 60 .

For every 10 you subtract , move up 1 row .

10 , is 1 tens . so, move up 1 rows .

lands on 50 which is the difference .

**Set C**

You can use mental math to subtract tens. Find 46 â€“ 10.

Subtract. Use mental math.

Question 5.

62 – 10 = ___

Answer:

62 – 10 = 52 .

Explanation :

You need to subtract 10, which is 1 tens.

Cross out 1 tens.

6 tens – 1 tens = 5 tens .

so, 62 – 10 = 52 .

Question 6.

89 â€“ 10 = ___

Answer:

Explanation :

You need to subtract 10, which is 1 tens.

Cross out 1 tens.

8 tens – 1 tens = 7 tens .

so, 89 – 10 = 79 .

Question 7.

27 – 10 = ___

Answer:

Explanation :

You need to subtract 10, which is 1 tens.

Cross out 1 tens.

2 tens – 1 tens = 1 tens .

so, 27 – 10 = 17 .

**Set D**

**Thinking Habits**

**Model with Math**

Can I use a drawing, diagram, table, or graph to model the problem? How can I make my model better if it doesn’t work?

Write an equation to solve. Use drawings or models to show your work.

Question 8.

A store has 50 toy boats. They sell 10 boats. How many toy boats does the store have now?

___ toy boats

Answer:

Number of toy boats = 50 .

Number of toy boats sold = 10 .

Number of toy boats left = 50 – 10 = 40 .

### Topic 11 Assessment Practice

Question 1.

Use the partial hundred chart to subtract tens.

A 70

B 60

C 50

D 40

Answer:

Option C .

Explanation :

Start at 70 .

For every 20 you subtract , move up 2 rows .

20 , is 2 tens . so, move up 2 rows .

lands on 50 which is the difference .

Question 2.

Use the place-value blocks. Find the difference.

A 10

B 20

C 30

D 40

Answer:

Option A

Explanation :

You need to subtract 30, which is 3 tens.

Cross out 3 tens.

4 tens – 3 tens = 1 tens .

so, 40 – 30 = 10 .

Question 3.

Use the open number line to solve. Show your work. Explain how you used the number line to find the answer. 60 – 20 = ____

Answer :

Explanation :

Start at 60 . Use place value take 20 as 2 groups of 10 .

count back 2 10’s from 60 .

we land on 40 which is the difference .

Question 4.

Solve the problem. Use any strategy. Explain why you picked the strategy. Write an addition equation to check your answer.

70 – 60 = ___

Answer:

Explanation :

Start at 70 . Use place value take 60 as 6 groups of 10 .

count back 6 10’s from 70 .

we land on 10 which is the difference .

Use mental math to solve. Then write an addition equation to check your answer.

Question 5.

23 â€“ 10 =

Answer:

Explanation :

23 is represented in ten frame .

to subtract 10 from 23 complete 1 ten frame is removed

then difference = 13 .

Question 6.

94 â€“ 10 = ___

Answer:

Explanation :

94 is represented in ten frame .

to subtract 10 from 94 complete 1 ten frame is removed

then difference = 84 .

Question 7.

51 â€“ 10 = ___

Answer:

Explanation :

23 is represented in ten frame .

to subtract 10 from 23 complete 1 ten frame is removed

then difference = 13 .

Use addition to solve each subtraction problem.

Question 8.

50 + ___ = 80, so 80 – 50 = ___.

Answer:

50 + 30 = 80,

so 80 – 50 = 30 .

Question 9.

20 + __ = 60, so 60 â€“ 20 = ___.

Answer:

20 + 40Â = 60,

so 60 â€“ 20 = 40.

Question 10.

A store has 90 sleds. It sells 30 sleds. How many sleds does the store have left?

Write an equation and solve. Use drawings or models to show your work.

___ sleds

Answer:

Number of sleds = 90 .

Number of sleds sold = 30

Remaining Number of sleds = 90 – 30 = 60 .

### Topic 11 Performance Task

**Fred’s Farm**

Fred sells different vegetables at his farm. He puts them in packages of 10.

Question 1.

Fred sells 3 packages of green peppers. How many green peppers does he have left to sell? Use the open number line to solve.

____ green Peppers

Answer:

Number of peppers in each bag contains = 10 peppers

Total number of green peppers = 7 bags .

Number of peppers bags sold = 3 bags .

Number of peppers bags left = 7 – 3 = 4 bags .

Question 2.

Fred feeds 10 carrots to his horse. How many carrots does he have left?

___ carrots

Answer:

Number of carrots = 6 bags

each bag contains 10 carrots .

Number of carrots = 6 Ã— 10 = 60 carrots

Number of carrots feeds to Horse = 10

Number of carrots left = 60 – 10 = 50 carrots .

Question 3.

Fred sells 30 potatoes on Monday. He sells the rest on Tuesday. How many potatoes were sold on Tuesday?

Use the partial hundred chart to solve the problem. Write the missing numbers in the equation.

___ potatoes

Answer:

Total Number of potatoes = 60

Number of potatoes sold on Monday = 30 .

Number of potatoes sold on Tuesday = ? = 60 – 30 = 30 potatoes .

Explanation :

Hundred chart is the best for subtraction problems for tens . it just move up 1 row for every 10 we subtract .

30 is 3 tens move up 3 rows .

we get 30 as the difference .

Question 4.

Debbie buys 4 packages of carrots at the farm. She uses 10 carrots to make soup. How many carrots does she have left? Solve the problem. Use one of the strategies you learned. Show how you solved the problem.

___ carrots

Answer:

Number of carrots in each package = 10

Number of packages = 4

Number of carrots in 4 packages = 10 + 10 + 10 +10 = 40 carrots .

Number of carrots used for soup = 10

Number of carrots left = 40 -10 = 30 carrots .

Hundred chart is used to solve the above problem .

Question 5.

Ty buys 36 vegetables. Lee buys 10 fewer vegetables than Ty. How many vegetables does Lee buy?

**Part A**

What strategy could you use to solve the problem?

Answer :

Hundred chart strategy .

**Part B**

Write an equation and solve the problem. Show how you solved it.

___ vegetables

Answer :

Number of vegetables ty bought = 36

Number of vegetables lee buys = 10 fewer vegetables than Ty. = 36 – 10 = 26 .

26 vegetables .