Unit 3, Lesson 12
Sums and Differences of Fractions
Grade 4
Warm-up
Find the value of each expression mentally.
Activity 1
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Find the number that makes each equation true. Show your reasoning.
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Write a sentence to describe your first step for finding the unknown value in each equation in the first problem.
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First step:
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First step:
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First step:
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First step:
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Compare and reflect on your first steps with your group. Did you make the same moves?
Discuss why you might have chosen the same way or a different way to start finding the missing values.
Activity 2
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Here are some addition and subtraction expressions. Sort them into two groups, based on whether you think it would be helpful to decompose a number to find the value of the expression.
- Not necessary or not helpful to decompose any number:
- Necessary or helpful to decompose one or more numbers:
- Choose at least one expression from each group and find their values. Show your reasoning.