## Lesson: Commutative and Associative Properties

Introducing the Concept

When students worked with addition facts last year, they recognized that fact families included both addition and subtraction facts. They also learned that by reversing the order of the addends, they could form related addition facts with the same sum. Revisit this pattern to help prepare students for addition and subtraction with regrouping.

**Materials:**large addition table showing sums from 0 to 20, student's hat and coat, highlighter

**Preparation:**Make a large addition table for the class to see. Addends should be from 0 to 10.

**Prerequisite Skills and Concepts:**Students should know basic addition facts to 20. See Grade 2: Addition and Subtraction Facts to 20.

Display the addition table for the class to see.