We included **H****MH Into Math Grade 1 Answer Key**** PDF** **Module 4 Lesson 4 Use Addition to Check Subtraction** to make students experts in learning maths.

## HMH Into Math Grade 1 Module 4 Lesson 4 Answer Key Use Addition to Check Subtraction

I Can use a related addition fact to check the answer to a subtraction problem.

**Spark Your Learning**

Martina has 11 fruits. 8 are mangos. The rest of the fruits are pineapples. How can you use related facts to find how many pineapples she has?

Answer:

Explanation:

Martina has 11 fruits

8 are mangos

The rest of the fruits are pineapples

I drew to show the difference

11 – 8 = 3

The related equations are

11 – 3 = 8

8 + 3 = 11

3 + 8 = 11

So, Martina has 3 pineapples.

Read the problem aloud. Have pairs of children choose tools to show the problem as addition and subtraction, Children should write related addition and subtraction facts that can be used to solve the problem.

**Build Understanding**

13 children play sports after school. 6 of them play soccer. The rest play basketball.

How many children play basketball after school?

A. How can you show the problem?

B. How can you write a subtraction equation to model the problem?

____ – ___ = ____

C. ___ children play basketball after school.

D. How can you write an addition equation to check your subtraction?

___ + __ = ___

Answer:

Explanation:

13 children play sports after school

6 of them play soccer

I drew to show the difference

13 – 6 = 7

7 children play basketball after school

The addition equation to check is 6 + 7 = 13.

**Turn and Talk** How does adding help you check subtraction?

**Step It Out**

1. 17 animals are in the park. 8 are squirrels. The rest are skunks. How many skunks are in the park?

A. Subtract to solve. Use any strategy.

17 – 8 = ___

B. Write a related addition fact to check your subtraction.

THINK: Use the same 3 numbers.

___ + ___ = ___

C. There are ____ skunks in the park.

Answer:

17 – 8 = 9

8 + 9 = 17

There are 9 skunks in the park

Explanation:

17 – 8 =

Make 10:

17 – 8

= 17 – 7 – 1

= 10 – 1

= 9

17 – 8 = 9

The related fact is 8 + 9 = 17

So, there are 9 skunks in the park.

**Check Understanding Math Board**

**Subtract. Then add to check your answer.**

Question 1.

Benny sees 16 dogs. 8 of them are young. The rest ape old. How many dogs are old?

16 – 8 = ___

___ + ___ = ___

___ old dogs

Answer:

16 – 8 = 8

8 + 8 = 16

8 old dogs

Explanation:

Benny sees 16 dogs

8 of them are young

The rest are old

16 – 8 =

Use doubles fact:

8 + 8 = 16

So, 16 – 8 = 8

There are 8 old dogs.

Add to check:

8 + 8 = 16

So, the difference of 16 and 8 is 8.

Question 2.

13 – 9 = ___

___ + ___ = ____

Answer:

13 – 9 = 4

9 + 4= 13

Explanation:

Make 10:

13 – 9

= 13 -3 – 6

= 10 – 6

= 4

13 – 9 = 4

So, 9+ 4 = 13

Add to check:

9 + 4 = 13

So, the difference of 13 and 9 is 4.

Question 3.

11 – 5 = ___

___ + ___ = ___

Answer:

11 – 5 = 6

5 + 6 = 11

Explanation:

Make 10:

11 – 5

= 11 – 1 – 4

= 10 – 4

= 6

11 – 5 = 6

So, 5 + 6 = 11

Add to check:

5 + 6 = 11

So, the difference of 11 and 5 is 6.

**On Your Own**

**Subtract. Then add to check your answer.**

Question 4.

**Open Ended** Dan builds 10 sandcastles. Some are small, and some are big. How many big sandcastles could he build?

10 – ___ = ___

___ + ___ = ____ ____ big sandcastles

Answer:

10 – 6 = 4

6 + 4 = 10

4 big sandcastles

Explanation:

Dan builds 10 sandcastles

Some are small, and some are big

Think 6 are small

Subtract 6 from 10 to find the big castles

10 – 6 = 4

So, 4 sand castles are big.

Question 5.

**Model with Mathematics** Melissa has 16 crayons. 7 are blue. The rest are red. How many crayons are red?

16 – 7 = ___

___ + ___ = ___ ___ red crayons

Answer:

16 – 7 = 9

7 + 9 = 16

9 red crayons

Explanation:

Melissa has 16 crayons

7 are blue

The rest are red

16 – 7 =

Make ten:

16 – 7

= 16 – 6 – 1

= 10 – 1

= 9

So, 16 – 7 = 9

There are 9 red crayons.

Question 6.

12 – 4 = ___

___ + ___ = ___

Answer:

12 – 4 = 8

8 + 4 = 12

Explanation:

12 – 4 =

Make 10:

12 – 4

= 12 – 2 – 2

= 10 – 2

= 8

12 – 4 = 8

Add to check

8 + 4 = 12

So, the difference of 12 and 4 is 8.

Question 7.

11 – 8 = ___

___ + ___ = ___

Answer:

11 – 8 = 3

8 + 3 = 11

Explanation:

11 – 8 =

Make 10:

11 – 1 – 7

= 10 – 7

= 3

So, 11 – 8 = 3

Add to check

8 + 3 = 11

So, The difference of 11 and 8 is 3.

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