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: Problem 1
Represent each fraction as a percent by completing the table. Use the two double number lines below to show your work.
| Fraction |   |   |   |   |   |
|----------|---|---|---|---|---|
| Percent  |   |   |   |   |   |
[IMG]
Problem 2
Answer the questions below using mental math. Use your double number lines from Anchor Problem 1 if you need to.
a.   What is
$$\frac{1}{2}$$
of 20?
b.   What is 50% of 20?
c.   What is 10% of 60?
d.   What is 20% of 60?
e.   What is
$$\frac{1}{4}$$
of 48?
f.   What is 25% of 48?
g.   What is 75% of 48?
h.   What is 10% of 125?
i.   A textbook that costs $36 is on sale for 25% off. How much money will you save?
Problem 3
Answer the questions below using mental math. Use your double number lines from Anchor Problem 1 if you need to.
a.   5 is 50% of what number?
b.   12 is 10% of what number?
c.   15 is 25% of what number?
d.   30 is 75% of what number?
e.   400 is 20% of what number?
f.   A coat is on sale for 10% off. You save $18. What was the original price of the coat?
Problem 4
Answer the questions below using mental math. Use your double number lines from Anchor Problem 1 if you need to.
a.   24 is what percent of 240?
b.   350 is what percent of 700?
c.   20 is what percent of 80?
d.   30 is what percent of 40?
e.   80 is what percent of 80?
f.   You saved $4 on a book that originally cost $16. What percent of the original cost did you save?


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