Grade 2 Unit 7
Lesson 10: Add within 1,000
CC BY 2021 Illustrative Mathematics®
Grade 2 Unit 7
Lesson 10: Add within 1,000
CC BY 2021 Illustrative Mathematics®
Find the value of each expression mentally.
199 + 23
198 + 24
297 + 25
395 + 27
Sort the cards into 2 groups with your partner.
Make a group of expressions that you agree the value is less challenging to find.
Make another group of expressions that you agree the value is more challenging to find.
Keep any expressions together that you and your partner disagree on.
Make a group of expressions that you agree the value is less challenging to find.
Make another group of expressions that you agree the value is more challenging to find.
Oh no! Diego spilled paint on his paper and now he can’t see all the digits in each of his equations.
What three-digit number makes the equation true? Show your thinking.

What three-digit number makes the equation true? Show your thinking.
Choose one expression and find the value by adding by place. Show your thinking.
Explain why you chose this sum.
Choose a different expression and find the value using a different method. Show your thinking.
Explain why you chose this sum.
Choose an expression that you feel is less challenging.
Find the value of the sum. Show your thinking.
Choose an expression that you feel is more challenging.
Find the value of the sum. Show your thinking.
Discuss one card you and your partner disagreed on. If you felt the expression was more challenging, explain why. If you felt the expression was less challenging, explain your method.