## Lesson: Two-Digit Subtraction With Regrouping

Developing the Concept

Once children are comfortable with using the different strategies in solving two-digit subtraction with regrouping, have them apply them to paper-and-pencil activities. The use of manipulatives, such as tens and ones blocks, craft sticks, and beans will be helpful. Children will use many of the same strategies that they used in Addition and Subtraction Facts to 20. Encourage children to share their thinking as they work through the examples.

**Materials:** tens and ones blocks or bundles of ten craft sticks and single craft sticks, pencils, paper

**Preparation:** Have the large hundred chart and number line you used for “Introducing the Concept” available.

**Prerequisite Skills and Concepts:** Children should know the subtraction facts to 20 and the strategies used in learning them.

**Wrap-Up and Assessment Hints**

Children need practice with two-digit subtraction and the strategies used. If the answer to a problem is not correct, ask the child to explain how he or she went about solving the problem. Find out what they are thinking and then select a strategy that builds on what they already know. Encourage children to check their subtraction by adding.