We included HMH Into Math Grade 2 Answer Key PDF Module 20 Relate Addition and Subtraction to Length to make students experts in learning maths. Rahanna is making a paper chain. So far, her paper chain has 42 links. Milo makes 12 links to add to Rahanna’s chain. How many links are in her paper chain now?

Solve this problem on a number line. Write an equation to model the work you did on the number line.
There are now ________ links in Rahanna’s paper chain.
There are now 54 links in Rahanna’s paper chain.
Explanation:
Rahanna paper chain has 42 links.
let n be the total number of chains
n =  42 + 12
n = 54
On the number line marked number 42 as the starting point and adding 12 to it.
so, moving forward on number line and counting numbers up to 12 that is 54

Turn and Talk

Rahanna is making a paper chain. So far, her paper chain has 42 links. she gave  12 links to Milo. Rahanna’s chain has how many links?
Explanation:
let n be the links that Rahanna  have
n = 42 – 12
n = 30
so, Rahanna’s chain has 30 links.

Complete these problems to review prior concepts and skills you will need for this module.

Use a Number Line to Count On

Question 1.
Count on to solve. Show your work on the number line.
14 + 8 = __________  Explanation:
On the number line marked number 14 as the starting point and adding  8 to it.
so, moving forward on number line and counting numbers up to 8 and reached the number 22.

Use a Number Line to Count Back

Question 2.
Count back to solve. Show your work on the number line.
25 – 13 = ____________  Explanation:
On the number line marked number 25 as the starting point and subtracting 13 to it
so, moving backward on number line and counting numbers up to 813 and reached the number 12.  