We included **HMH Into Math Grade 2 Answer Key PDF** **Module 20 Lesson 4 Add and Subtract Lengths in Centimeters **to make students experts in learning maths.

## HMH Into Math Grade 2 Module 20 Lesson 4 Answer Key Add and Subtract Lengths in Centimeters

I Can use a number line to represent and solve addition and subtraction problems about length in centimeters.

**Spark Your Learning**

Draw a diagram to solve the problem.

Mr. Kimble cut __________ centimeters of fabric.

Mr. Kimble has 66 centimeters of fabric. He cuts some fabric to use for a cushion. He has 27 centimeters of the fabric left. How much fabric did Mr. Kimble cut for the cushion? Draw a diagram to solve. Then write an equation to represent the problem and your answer.

Answer:

Mr. Kimble cut 39 centimeters of fabric.

Explanation:

Mr. Kimble has 66 centimeters of fabric.

He cuts some fabric to use for a cushion.

He has 27 centimeters of the fabric left.

let n be the fabric that was cut

n = 66 – 27

n = 39

**Build Understanding**

Question 1.

A worm is 12 centimeters long. A second worm is 9 centimeters longer than the first worm. How long is the second worm?

Answer:

A. How can you show the lengths of the worms on the number line?

Answer:

B. How does your drawing represent the problem?

Answer:

12 + 9 = 21 is the length of second worm.

C. Write an equation to model and solve this problem. Use a for the unknown number.

Answer:

= 12 + 9

D. The second worm is ___________ centimeters long.

Answer:

The second worm is 21 centimeters long.

Explanation:

A worm is 12 centimeters long.

A second worm is 9 centimeters longer than the first worm.

let be the unknown length of the second worm

= 12 + 9

= 21

21 centimeters is the second worm

**Turn and Talk** How is drawing a diagram on a number line like making a bar model?

Answer:

No, it is showing like a line.

**Step It Out**

Question 1.

Mrs. Lewis has some wire that is 41 centimeters long. She cuts 18 centimeters off the wire to use. How much wire is there now?

A. Draw a line to show how long the wire is before Mrs. Lewis cuts it.

Answer:

41 centimeters is the wire

B. Draw another line to show how much of the wire Mrs. Lewis cuts.

Answer:

C. Write an equation using for the unknown number.

Answer:

= 41 – 18

D. The wire is _________ centimeters now.

Answer:

The wire is 23 centimeters now.

Explanation:

Mrs. Lewis has some wire that is 41 centimeters long.

Then she cuts 18 centimeters off the wire to use.

= 41 – 18

= 23

23 centimeters wire is there now

**Check Understanding**

Question 1.

Rashida’s yarn is 36 centimeters long. She cuts off 14 centimeters. How long is the yarn now? Write an equation using for the unknown number. Use the number line to solve.

____________ ______________ centimeters

Answer:

36 – 14 = 22 centimeters

Explanation:

Rashida’s yarn is 36 centimeters long.

She cuts off 14 centimeters.

is the unknown yarn length

= 36 – 14

= 22

22 centimeters long is the yarn now

**On Your Own**

Use the number line to solve. Write an equation using for the unknown number. Solve.

Question 2.

Gerard and Ami put trains together on a track. Gerard’s train is 14 centimeters long. Ami’s train is 12 centimeters long. How long are the two trains put together?

_____________ centimeters

Answer:

26 centimeters

Explanation:

Gerard’s train is 14 centimeters long.

Ami’s train is 12 centimeters long.

is the unknown length

= 14 + 12

= 26

Question 3.

**Use Tools** Brynn builds a train track that is 74 centimeters long. Then she takes away 18 centimeters of track. How long is the train track now?

___________ centimeters

Answer:

56 centimeters

Explanation:

Brynn builds a train track that is 74 centimeters long.

Then she takes away 18 centimeters of track.

is the unknown length

= 74 – 18

= 56

56 centimeters is the track now.

**I’m in a Learning Mindset!**

Do I share and accept strategies from others?

Answer:

No, we have followed the number line concept.