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 True or False is for students to demonstrate strategies they have for using equivalent fractions to add and subtract fractions with different denominators. These mental calculations prepare students for working with more complex common denominators during this lesson.
Launch
Display one statement.
“Give me a signal when you know whether the statement is true and can explain how you know.”
1 minute: quiet think time
Activity
Share and record answers and strategy.
Repeat with each statement.
Student Facing
Decide if each statement is true or false. Be prepared to explain your reasoning.
\(\frac{1}{4}+\frac{2}{4}=\frac{3}{4}\)
\(\frac{1}{2}+\frac{1}{4}=\frac{2}{4}\)
\(\frac{3}{4}-\frac{1}{2}=\frac{2}{4}\)
Student Response
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Activity Synthesis
“How can we find the correct value of
\(\frac{3}{4}-\frac{1}{2}\)
?” (
\(\frac{1}{2}=\frac{2}{4}\)
so
\(\frac{3}{4}-\frac{2}{4}=\frac{1}{4}\)
.)


aligns: no