# Section B: Practice Problems Add and Subtract on a Number Line

## Section Summary

Details

In this unit, we have solved all types of problems and represented them in different ways. We represented addition and subtraction on the number line and made connections to equations and strategies. When adding and subtracting within 100, we can use diagrams, base-ten blocks, number lines, and equations to make sense of stories and situations and to show our thinking. They are all connected.

## Problem 1 (Lesson 7)

Which equation does the number line represent? Explain your reasoning.

## Problem 2 (Lesson 8)

Here is a number line.

1. Write an equation that the number line represents.

2. Explain how your equation matches the number line.

## Problem 3 (Lesson 9)

1. Explain or show how each number line represents the value of .

2. Which method do you prefer to calculate ?

## Problem 4 (Lesson 10)

Find the value of . Represent your thinking on the number line.

## Problem 5 (Lesson 11)

Find the value of in two different ways. Show your thinking on the number lines.

1. Method 1:

2. Method 2:

## Problem 6 (Lesson 12)

I started at a number on the number line and jumped back 37. I landed at 26. Where did I start?

1. Write an equation with a ? for the unknown.

2. Find the number that makes the equation true.

3. Represent your thinking on the number line.

## Problem 7 (Lesson 13)

There are 18 students in the classroom. Then 13 more students join them.

1. Label the tape diagram to match the story.

2. Label the number line to match the story.

3. How are the tape diagram and number lines the same? How are they different?

4. How many students are in the classroom now?

## Problem 8 (Exploration)

1. Using addition or subtraction, how many equations can you make with these three numbers: 20, 13, 7?

2. Draw number lines to match each of the equations you wrote.

3. How are the number lines the same? How are they different?

## Problem 9 (Exploration)

1. Write a story problem that can be solved with this number line.

2. Explain how the number line solves your story.