# Lesson 3

Are the Expressions Equal?

### Lesson Purpose

The purpose of this lesson is for students to identify expressions that are equal.

### Lesson Narrative

In previous lessons students identified sums they know and sums they don’t yet know. They applied the commutative property to add within 10. The purpose of this lesson is for students to interpret equations with expressions on both sides of the equal sign. In Activity 1, students sort addition expressions within 10 by the value of the sum and discuss how expressions with the same numbers in a different order can be written as an equation. In Activity 2, students determine whether equations with addition expressions on both sides of the equal sign are true or false.

Students complete the cool down before the lesson synthesis.

• Representation
• MLR8

### Learning Goals

Teacher Facing

• Interpret equations with expressions on both sides of the equal sign.
• Understand and use the commutative property.

### Student Facing

• Let’s think about how expressions can be equal.

### Required Materials

Materials to Gather

### Required Preparation

Activity 1:

• Each student needs their addition expression cards from a previous lesson.

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

It is common for students to think that the equal sign means that the answer comes next. What evidence have students given that they have a true understanding of the meaning of the equal sign? How might you adjust instruction to clarify this understanding?