# Lesson 16

Round Numbers

### Lesson Purpose

The purpose of this lesson is for students to round multi-digit whole numbers within 1,000,000 to the nearest 1,000, 10,000, and 100,000.

### Lesson Narrative

In grade 3, students rounded whole numbers to the nearest 10 and 100. In previous lessons, they worked to find the closest multiples of powers of 10. Here, students build on this work to round whole numbers to the nearest 1,000, 10,000, and 100,000. Students revisit the convention of rounding up when a number is exactly halfway between two consecutive multiples of a power of 10.
• Action and Expression
• MLR8

Activity 1: Round to What?

### Learning Goals

Teacher Facing

• Round multi-digit whole numbers to the nearest 1,000, 10,000, and 100,000.

### Student Facing

• Let’s round some large numbers.

### Lesson Timeline

 Warm-up 10 min Activity 1 20 min Activity 2 15 min Activity 3 20 min Lesson Synthesis 10 min Cool-down 5 min

### Teacher Reflection Questions

How readily did students transition from reasoning about nearest multiples using number lines to reasoning numerically and rounding? What progress have you seen them make in using representations flexibly to support their thinking? What did students say or do that showed this progress?

### Suggested Centers

• Mystery Number (1–4), Stage 5: Six-digit Numbers (Addressing)
• Tic Tac Round (3–5), Stage 1: Nearest Ten or Hundred (Supporting)