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
This Number Talk encourages students to use what they know about the meaning of fractions and about properties of operations to mentally relate fractions that are equivalent to whole numbers.
Launch
Display one fraction.
“Give me a signal when you have an answer and can explain how you got it.”
1 minute: quiet think time
Activity
Record answers and strategy.
Keep fractions and work displayed.
Repeat with each fraction.
Student Facing
Find the whole number that each fraction is equivalent to.
\(\frac{16}{1}\)
\(\frac{16}{2}\)
\(\frac{16}{4}\)
\(\frac{20}{4}\)
Student Response
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Activity Synthesis
“How did the earlier fractions help you find the whole number for the last fraction?”
Consider asking:
“Did anyone have the same strategy but would explain it differently?”
“Did anyone approach the problem in a different way?”


aligns: no