# Lesson 15 Decompose a Ten and a Hundred to Subtract

Let’s subtract within 1,000.

## Warm-up Choral Count: Hundreds and Tens

Count back by 10, starting at 590.

What patterns do you see?

## Activity 1 Elena’s Thinking

Elena’s thinking:

Step 1:

Step 2:

Step 3:

Use base-ten blocks or a base-ten diagram to show Elena’s steps.

Finish Elena’s work to find the value of

. What is another way you could use numbers or equations to show subtracting by place to find the value of

?

## Activity 2 Walk About and Subtract

Find someone with a different number than you.

Find the difference between your numbers.

Show your thinking.

Trade cards and find a new partner.

Partner 1:

Partner 2:

Partner 3:

## Practice Problem

## Problem 1

Find the value of each difference. Show your thinking.