# Section B: Practice Problems Subtract Within 1,000

## Section Summary

## Details

In this section, we learned algorithms to subtract numbers within 1,000. We also learned that we can choose whether to use an algorithm or another strategy for subtracting based on the numbers.

## Problem 1 (Lesson 7)

Find the value of

## Problem 2 (Lesson 8)

Here is a subtraction calculation.

Explain what the 400 above the 500 means.

Explain what the 140 above the 40 means.

Explain how the calculation works to find

.

## Problem 3 (Lesson 9)

Write 518 and 346 in expanded form.

Use the expanded form to find the difference of the two numbers.

## Problem 4 (Lesson 10)

Use an algorithm of your choice to find the value of

. Use an algorithm of your choice to find the value of

.

## Problem 5 (Lesson 11)

Use an algorithm of your choice to find the value of each difference.

## Problem 6 (Lesson 12)

Use a strategy or algorithm of your choice to find the value of each difference.

## Problem 7 (Exploration)

Here is Noah’s way to find the value of

The answer is

Explain why Noah’s method works.

Use Noah’s method to calculate

.

## Problem 8 (Exploration)

Find the value of

. Explain or show your reasoning. How is this problem different from other subtraction problems you have solved?