# Section B: Practice Problems Decompose to Subtract

## Section Summary

Details

In this section, we practiced subtracting two-digit numbers. We learned that when there are not enough ones to subtract by place, you can decompose 1 ten for 10 ones. We used base-ten blocks and base-ten diagrams to show our thinking.

## Problem 1 (Lesson 5)

Find the value of each difference. Show your thinking.

## Problem 2 (Lesson 6)

Here is Mai’s work with a subtraction expression.

1. What subtraction expression does Mai’s diagram show?

2. What is the value of the expression?

3. Use Mai’s method to find the value of .

## Problem 3 (Lesson 7)

Find the value of . Show your thinking. Use blocks if it helps.

## Problem 4 (Lesson 8)

Here is how Clare found the value of .

Here is how Han found the value of .

How are Han’s and Clare’s calculations the same?

How are they different?

## Problem 5 (Lesson 9)

Find the value of each expression. Show your thinking.

## Problem 6 (Exploration)

Here is Han’s method for finding the value of .

1. Show each step of Han’s work with base-ten blocks.

2. Explain or show why Han’s method works.

## Problem 7 (Exploration)

Here is Jada’s method for finding the value of .

1. Explain why Jada’s method works.

2. Use Jada’s method to find the value of .