Log inSign up for FREE
Library

Unit 3 - Lesson 9 - Grade 3: Illustrative Mathematics

Last updated 9 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

1

Explain your reasoning.

1

125 + 200 = 200 + 125

1

Explain your reasoning.

1

300 - 100 = 100 - 300

1

Explain your reasoning.

Revise Subtraction Work

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

1

What error do you see in Lin's work?

1

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.
1

283 - 159

1

425 - 192

1

639 - 465

1

591 - 128

1

832 - 575

Cool Down: How Did Andre Subtract?
1

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


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