# Expressions

#### Materials

CCB Mathematics pages 134 - 139

#### Standards

MP.1

Use properties of operations to generate equivalent expressions.

#### Objectives

Translate between verbal and symbolic representations of expressions

Simplify expressions

Evaluate expressions

#### Key Concept

Mathematical and real-world situations can be represented by expressions that can be amplified and evaluated.

#### Vocabulary

Tier 2 | Variable |
---|---|

Tier 3 | Algebraic Expression Coefficient Constant Term Mathematical Expression Symbolic Expression Verbal Expression |

## Before Lesson

To simplify and evaluate expressions, students will need to know and apply the order of operations. Ask a volunteer to remind the class of the order of operations (parentheses, exponents, multiplication, division, addition, subtraction). Then practice a few two- and three-step problems. For example: 5-8÷2; 4+5x-6; -2.3-4x1.2.

## Background

Tell students that mathematical expressions are phrases or parts of sentences, just as verbal expressions are phrases and parts of sentences. Write a sentence and an equation on the board, such as The red fox leaped among the flowers in the meadow and (2x4)+16/8=x. Circle among the flowers and in the meadow in the sentence. Circle (2x4) and 16/8 in the equation. Explain that all four are expressions, and ask students to describe the difference among them. Then explain that the mathematical expressions can be simplified or evaluated. Ask: How can you simplify 16/8?

## Guided Practice

- Verbal and Symbolic Representations of Expressions
- Identify Key Words
- Evaluate Expressions

## Core Skill

**Evaluate Expressions:** After reading the sidebar, discuss with students how these steps for writing an expression are similar to or different from the steps they used in the Five-Step Approach. A similarity is that they need to be completed in order. They need to clearly explain how the problem is solved. Discuss the importance of each step in the examples.

**Make Sense of Problems:** After students read the sidebar, lead a class discussion on how they have used key words to help solve problems so far. Then have pairs use key words to write simple math problems for each other, exchange, and solve.

## Extension

**Write Verbal Statements:** Have students work in pairs to write verbal situations for the problems in the Think about Math activity on page 137. Have volunteers read them aloud.

**Interpret Variable:** Have students use print and online resources to answer the question: What is a variable? Have students create a presentation to explain the concept of a variable to students who have never studied the algebraic concept. Encourage students to use free online tools to create their presentations.