# 4. Write and evaluate algebraic expressions to solve problems (A)

## About this lesson

Lesson objective: Solve problems by writing and evaluating an algebraic expression

This lesson provides an opportunity for students to apply their knowledge and understanding of algebraic expressions to a real-life situation. Students are asked to write a general expression for the volume of a container and then use their expressions to help a chef find the best-sized container for her pantry ingredients.

Key Concept students will use:

- Algebraic expressions can represent both a “recipe” and a quantity (that we may or may not be able to name with a number).

Skills students will use:

- write an expression describing the volume of a rectangular prism
- find the volume of a rectangular prism (Grade 5, Unit 1)
- use order of operations to simplify expressions containing exponents

Students engage in Mathematical Practice 2 (reason abstractly and quantitatively) as they use the context of a real-world problem to write an expression and then evaluate the expression at specific values to find the best solution to the problem.

**Key vocabulary: **

- evaluate
- expression
- order of operations
- value
- volume