Unit 7, Lesson 16
Subtract within 1,000
Grade 2
Activity 1
Lin’s diagram
Jada’s equations
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- Discuss how Jada’s equations match Lin’s diagram.
- Finish Jada’s work. Find the value of
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Jada is thinking about how to find the value of
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Jada knows a way to count on to find the difference. She shows her thinking, using a number line.
Explain Jada’s thinking.
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Jada says she can’t decompose to find the value of , because there aren’t any tens. Do you agree? Show your thinking, using objects, drawings, numbers, or words.
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Student Section Summary
We learned ways to subtract 3-digit numbers, using place value. We used base-ten blocks, diagrams, and equations to subtract hundreds from hundreds, tens from tens, and ones from ones. We decomposed a hundred, a ten, or both to subtract by place. We looked closely at numbers in expressions. We planned how to decompose. We used friendly numbers or the relationship between addition and subtraction.
Base-Ten Diagram
Unit Form