Lesson objective: Understand that different strategies can be used to solve addition equations.

Students bring prior knowledge of number partners that equal 10 from K.OA.A.4. This prior knowledge is extended to support the addition strategy of making a ten as students decompose the second addend in a specific way to compose 10 with the first addend. Students also transition from a number track to a number line to count on as an addition strategy. A conceptual challenge students may encounter is thinking there is only one way to add. Students may also struggle with choosing the most efficient strategy for the equation they are trying to solve.

The concept is developed through work with a number track/a number line and a representation of decomposing one addend to make a ten, which support students in visually seeing the distinction between these two strategies.

This work helps students deepen their understanding of operations because students are developing different strategies to become more fluent in adding numbers.

Students engage in Mathematical Practice 7 (Look for and make use of structure) as they determine the best strategy to use to solve a particular problem. Students will learn when to use counting on verses making a ten as a strategy to add numbers efficiently.

**Key vocabulary:**

- compose
- counting on
- decompose
- make a ten
- number line

**Special materials needed:**

- counters or interlocking cubes
- number line