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Unit 3 - Lesson 16 - Grade 3: Illustrative Mathematics

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12 Questions
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Grade 3 Unit 3
Lesson 16: Round and Round Again
CC BY 2021 Illustrative Mathematics®
Grade 3 Unit 3
Lesson 16: Round and Round Again
CC BY 2021 Illustrative Mathematics®
Lesson: Round and Round Again

Number Talk: More Groups, Fewer Groups (Warm Up)

Find the value of each expression mentally.
1.

5 x 7

2.

4 x 7

3.

6 x 7

4.

4 x 8

All the Numbers

5.

What are all the numbers that would round to 50 if you're rounding to the nearest ten? You can use this number line if it helps you.

6.

What are all the numbers that would round to 70 if you're rounding to the nearest ten?

7.

What are all the numbers that would round to 600 if you're rounding to the nearest hundred?

If you finish early, find the numbers that would round to 100 and to 500 if you’re rounding to the nearest hundred. Compare your lists with a partner's lists and discuss patterns you see.

What’s My Mystery Number?

8.

Write down a number between 100 and 1,000.

This is your mystery number.

Don't tell or show your mystery number to anyone.

Write down 3 clues about your mystery number by finishing these sentences:
9.
My mystery number is __________
10.
My mystery number rounds to _______.
11.
My mystery number is between_______and_______.
Play What’s My Number?
  1. Read the clues for your mystery number.
  2. Starting with the person on your right, have every member in your team try to guess your mystery number and explain their reasoning.
  3. If they haven’t guessed the mystery number by the time the last person shares, reveal the mystery number.
  4. Repeat steps 1 through 3 with the next person in the group reading the clues for their mystery number.
Cool Down: What is Clare’s Mystery Number?
12.

Clare says she’s thinking of a mystery number and gives these three clues:
  • The number is even.
  • The number rounded to the nearest ten is 270.
  • The number is between 260 and 280.
What are 2 numbers that could be Clare's mystery number?