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Unit 3 - Lesson 9 - Grade 3: Illustrative Mathematics

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Last updated 2 months ago
14 Questions
Note from the author:
Grade 3 Unit 3
Lesson 9: Subtraction Algorithms (Part 2)
CC BY 2021 Illustrative Mathematics®
Grade 3 Unit 3
Lesson 9: Subtraction Algorithms (Part 2)
CC BY 2021 Illustrative Mathematics®
Lesson: Subtraction Algorithms (Part 2)

True or False: Does It Commute? (Warm Up)

Decide if each statement is true or false. Be prepared to explain your reasoning.
1.

4 x 5 = 5 x 4

2.

Explain your reasoning.

3.

125 + 200 = 200 + 125

4.

Explain your reasoning.

5.

300 - 100 = 100 - 300

6.

Explain your reasoning.

Revise Subtraction Work

Lin’s work for finding the value of is shown.

7.

What error do you see in Lin's work?

8.

What would you tell or show Lin so she can revise her work?

Try the Algorithm

Here is a subtraction algorithm you saw in an earlier lesson:


Try using this algorithm to find the value of each difference. Show your reasoning. Organize it so it can be followed by others.
9.

283 - 159

10.

425 - 192

11.

639 - 465

12.

591 - 128

13.

832 - 575

Cool Down: How Did Andre Subtract?
14.

Andre found the value of 739 - 255. His work is shown.


Explain how he subtracted and the value he found for 739 - 255.