Lesson 16

Round and Round Again

Lesson Purpose

The purpose of this lesson is for students to use their understanding of rounding to consider all the numbers that round to a given number.

Lesson Narrative

Students deepen their understanding of rounding to go beyond accurately rounding individual numbers as they think about what numbers round to a given number. Working backward from a multiple of 10 or 100 allows students to think about the relative distance of numbers and the range of numbers that round to the given multiple of 10 or 100. Students then use this understanding to write clues to help their classmates guess a mystery number. What a number rounds to becomes a useful way to describe a number in this game.

• Action and Expression
• MLR8

Learning Goals

Teacher Facing

• Recognize and generalize patterns in the rounding of whole numbers within 1,000.

Student Facing

Let’s look for patterns in rounding.

Required Materials

Materials to Gather

Required Preparation

Activity 2:

• Each student needs an index card.

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

What was the best question you asked students today? Why would you consider it the best one based on what students said or did?

Suggested Centers

• Target Numbers (1–5), Stage 7: Subtract Hundreds, Tens, or Ones (Addressing)