Lesson 8

Round Decimals

Lesson Purpose

The purpose of this lesson is for students to round to the nearest whole, tenth, and hundredth.

Lesson Narrative

In this lesson students build on prior understandings of rounding whole numbers to round decimals to different place values. In the first activity students label tick marks on number lines and reason about the possible value of a point on the number line. They consider which two decimals the point lies between, which of those decimals is closer, and how much closer. In the second activity, students round numbers to different places, first using the number lines provided and then using place value reasoning, supported by number lines if students choose to use them. A third activity provides extra rounding practice.

• Action and Expression
• MLR8

Learning Goals

Teacher Facing

• Round decimals to the nearest whole, tenth, and hundredth.

Student Facing

• Let’s round decimals to the nearest whole, tenth, and hundredth.

Building On

Lesson Timeline

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

Teacher Reflection Questions

What did you see or hear in your students’ responses today that showed evidence of their understandings of place value?

Suggested Centers

• Mystery Number (1–4), Stage 6: Decimals (Addressing)
• Get Your Numbers in Order (1–5), Stage 5: Decimals (Addressing)