# Lesson 5

Compose and Decompose Numbers Within 1,000

### Lesson Purpose

The purpose of this lesson is for students to compose and decompose three-digit numbers in different ways.

### Lesson Narrative

In previous units, students represented three-digit numbers by composing and decomposing units using base-ten blocks, base-ten diagrams, and equations.

In this lesson, students compose and decompose three-digit numbers using base-ten blocks and other representations that make sense to them. Throughout the lesson, students are encouraged to show and deepen their understanding of place value by composing and decomposing units.

• Action and Expression

Activity 2: Let Me Count the Ways

### Learning Goals

Teacher Facing

• Compose and decompose numbers within 1,000.
• Represent numbers within 1,000 in different ways.

### Student Facing

• Let’s represent numbers in many different ways.

### Required Materials

Materials to Gather

### Lesson Timeline

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

### Teacher Reflection Questions

In this section, students are working to develop fluency when adding and subtracting within 100. How does the work of the lesson help deepen students understanding of place value? How will the work of this lesson help students become more fluent when adding and subtracting within 100?

### Print Formatted Materials

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