standard_description: Interpret multiplication as scaling (resizing), by:
- Explaining why multiplying a given number by a fraction greater than 1 results in a product greater than the given number (recognizing multiplication by whole numbers greater than 1 as a familiar case); explaining why multiplying a given number by a fraction less than 1 results in a product smaller than the given number; and relating the principle of fraction equivalence a/b = (n×a)/(n×b) to the effect of multiplying a/b by 1.
- Comparing the size of a product to the size of one factor on the basis of the size of the other factor, without performing the indicated multiplication.
problem_activity: Narrative
The purpose of this activity is for students to reason about adding fractions with unlike denominators to add two equations to a partially-completed True or False activity. If there is time, students can facilitate their True or False with another group.
Launch
Groups of 2 or 4
“Now you will work with your group to complete a True or False activity. This activity has two equations missing. Decide on equations that would complete the True or False and write them on the blank lines.”
Activity
10 minutes: small-group work time
As students work, monitor for groups who discuss and design equations based on some of the following:
They create equations where the fractions on one side of the equation have unlike denominators and the other side consists of fractions with like denominators.
They create an equation where the common denominator is appropriate, but the corresponding fraction used is not equivalent.
They create an equation that is similar to a previous equation.
They create an equation where a similar strategy can be used to determine if it’s true.
Student Facing
Write two equations to complete the True or False task. Be prepared to share your reasoning for the equations.
\(\frac{8}{14}+\frac{3}{7}=\frac{4}{7}+\frac{3}{7}\)
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Student Response
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Activity Synthesis
Choose small groups to share that had different reasons for their equations.
Ask students to share their completed True or False and ask the class to share reasons for the equations.
As each group shares, continually ask others in the class if they agree or disagree and the reasons why.


aligns: no