# Lesson 7 Compose a Larger Unit

Let’s add three-digit numbers and compose tens or hundreds.

## Warm-up How Many Do You See: Are They the Same?

How many do you see? How do you see them?

## Activity 1 Compose a Ten or a Hundred

Find the value of each expression. Show your thinking. Use base-ten blocks if it helps.

Compare your thinking with your partner.

## Activity 2 Walk About and Add

## Problem 1

Directions:

Find a partner and record your numbers to make an expression.

Discuss if you think you would need to compose a ten or a hundred when adding your numbers.

Find the value of the sum. Show your thinking.

+

Will you need to compose a ten? Yes or No

Will you need to compose a hundred? Yes or No

Find the value of the sum. Show your thinking.

## Problem 2

+

Will you need to compose a ten? Yes or No.

Will you need to compose a hundred? Yes or No.

Find the value of the sum. Show your thinking.

## Problem 3

+

Will you need to compose a ten? Yes or No

Will you need to compose a hundred? Yes or No

Find the value of the sum. Show your thinking.

## Practice Problem

## Problem 1

Find the value of each sum. Explain your reasoning.