Lesson objective: Write numerical expressions about real-life or mathematical situations.

This lesson helps to build fluency with writing numerical expressions. Pictures of items are used here because they help students visualize the items and amounts discussed in the expressions. This work develops students' understanding that expressions can be written to describe real-life or mathematical situations.

Students engage in Mathematical Practice 2 (reason abstractly and quantitatively) as they reason about the meaning of expressions and how real-life and mathematical situations are translated into numerical expressions.

**Key vocabulary:**

- calculation
- evaluate
- numerical expression

**Special materials needed:**

- counters or unit cubes can be used if teachers want to have students represent the numerical expressions with a manipulative