# Lesson 12 Subtract Strategically

Let’s consider when to use algorithms and when to use other strategies to subtract.

## Warm-up Number Talk: Threes

Find the value of each expression mentally.

## Activity 1 How Would You Subtract?

Use a strategy or algorithm of your choice to find the value of each difference. Show your reasoning. Organize it so it can be followed by others.

## Activity 2 Greatest Difference, Smallest Difference

Decide with your partner whether you will try to make the greatest difference or smallest difference.

Take turns spinning and recording a digit in the hundreds, tens, or ones place. Continue until your numbers are complete.

Find the difference.

Compare your values.

Write a comparison using >, <, or =.

Play again.

## Practice Problem

## Problem 1

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