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Unit 7 - Lesson 14 - Grade 2: Illustrative Mathematics

Last updated 9 months ago
9 questions
Note from the author:
Grade 2 Unit 7
Lesson 14: Think Before You Subtract
CC BY 2021 Illustrative Mathematics®
Grade 2 Unit 7
Lesson 14: Think Before You Subtract
CC BY 2021 Illustrative Mathematics®
Lesson: Think Before You Subtract

Which One Doesn’t Belong: Blocks and Blocks and Blocks (Warm Up)

1

Which one doesn’t belong?

Agree to Disagree

Tyler and Clare are subtracting by place to find the value of 244 - 67. Tyler says he will decompose before
he starts. Clare says she agrees.

The diagrams show each student’s first step.

1

What is the same about Tyler and Clare’s diagrams? What is different?

1

Work together to complete Tyler’s way and Clare’s way to find the value of 244 - 67.

1

What do Tyler and Clare’s diagrams look like after the last step? What is the same about these diagrams? What is different?

Sort and Subtract

Here is a base-ten diagram for 341.

1

Andre wants to use diagrams and subtract by place to find the value of 341 - 68. He says he will decompose a ten and a hundred to subtract.

Why do you think he said that?

1

Andre only wants to use a diagram to subtract by place if he will decompose a unit. Help Andre sort the expressions into groups. If you are not sure, use base-ten blocks or a diagram to help.

1

Find the value of 1 expression from each group.

Show your thinking.

Cool Down: Decompose? Maybe.
Han wants to subtract by place to find the value of these expressions.

1

Han wants to start by subtracting without decomposing any units.

Which expression should he choose?

1

Find the value of the expression. Show your thinking.