Unit 9 - Lesson 2 - Grade 2: Illustrative Mathematics

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Last updated 7 months ago

5 questions

Note from the author:

Grade 2 Unit 9
Lesson 2: Fluency Flip
CC BY 2021 Illustrative Mathematics®

Instructions

Grade 2 Unit 9
Lesson 2: Fluency Flip
CC BY 2021 Illustrative Mathematics®

Lesson: Fluency Flip

True or False: Sums within 20 (Warm Up)

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

8 + 5 = 8 + 2 + 5

8 + 5 = 8 + 2 + 3

8 + 5 = 10 + 3

Heads Up: Make 20

Directions:
• Partner A holds a card on their forehead without looking.
• Partner B names the number that you can add to the number on the card to get 20.
• Partner A says the number on their card.

Record an equation to represent how you found the unknown addend.

Cool Down: Just the Facts

Unit 9 - Lesson 2 - Grade 2: Illustrative Mathematics

True or False: Sums within 20 (Warm Up)

8 + 5 = 8 + 2 + 5

8 + 5 = 8 + 2 + 3

8 + 5 = 10 + 3

Heads Up: Make 20

Record an equation to represent how you found the unknown addend.

Explain how you can use facts you know to find the value of sums and differences you don’t know right away.