Lesson objective: Students will be able to use addition and subtraction to solve money story problems.

Students bring prior knowledge of adding and subtracting to solve story problems from 2.OA.A.1. This prior knowledge is extended to using addition and subtraction as students work on solving real-world money story problems. A conceptual challenge students may encounter is determining which operation to use to accurately solve the problems.

The concept is developed through work with coins and number lines, which supports students' representation of the money story problem and the operation used to solve it.

This work helps students deepen their understanding of operations because students use addition and subtraction to put together or take away amounts of money.

Students engage in Mathematical Practice 4 (Model with mathematics) as they use representations (drawings or number lines) to show how they added or subtracted to put together or take away amounts of money.

**Key vocabulary:**

- addition
- number line
- put together
- story problem
- subtraction
- take away

**Special materials needed:**

- dollars and coins
- hundreds grid
- number lines (filled in and blank)
- scratch paper