## Lesson: Addition and Subtraction Facts to 20

Introducing the Concept

Begin by focusing on addition facts. When children have become proficient with these, introduce the corresponding subtraction facts. Set the facts in the context of a story. Act them out and encourage children to join in the activity. If manipulatives are available, you may want to repeat the activities with different numbers while children use manipulatives to act them out. Once children are comfortable with all the facts, encourage them to use the fact cards for practice.

**Materials:** fact cards; primary and regular crayons, 10 each

**Preparation:** Prepare fact cards for addition facts through 20 and for the corresponding subtraction facts. Have 10 large and 10 small crayons available for demonstration.

**Prerequisite Skills and Concepts:** Children should have a good foundation in number relationships.