Lesson objective: Add numbers within 20 using the addition strategies.

This lesson helps to build fluency with whole number addition. Ten frames and number bonds are used here because they highlight when and how to use the make-a-ten addition strategy. This work develops students' understanding that using strategies can make adding easier.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they decompose one addend to make-a-ten with the other addend. Students will build on their knowledge of mentally adding a single digit to 10 and use a structured equation model to learn the steps to apply the make-a-ten strategy to solve addition equations.

**Key vocabulary:**

- decompose
- equation
- make a ten
- ten frame
- number bonds