Lesson objective: Relate counting on to subtraction to solve subtraction situations.

This lesson helps to build procedural skill with counting to subtract. Modeling with number sentences is used here because it supports relating addition and subtraction to one another through using numbers in different orders. This work develops students' understanding that when we think about how many we counted on, we are using counting to subtract.

Students engage in Mathematical Practice 6 (Attend to precision) as they use the counting on strategy to model subtraction situations with number sentences and by relating subtraction to addition. Students will explain how they use the counting on strategy to find differences in the Subtract to 10 game with their partner.

**Key vocabulary:**

- add
- counting on
- difference
- number sentence
- subtract

**Special materials needed:**

- counters
- number cards from 1 to 9
- recording sheets