Three Ways to Write It

Finn reads this

The same amount can be written three ways: as a percent, as a fraction, and as a decimal. They all say out of 100.

Percent, fraction, decimal

Finn reads this

30 percent is 30 over 100, and 30 hundredths is 0.30. 25 percent is 25 over 100, which simplifies to one fourth, and 25 hundredths is 0.25. Same amount, three outfits.

ElleMath-speak

To convert a percent to a decimal, divide by 100.

FinnPlain English

Move the decimal point two places left. 30 percent becomes 0.30.

A fraction to a percent goes through the decimal

Finn reads this

Three eighths is not out of 100, so divide first. 3 divided by 8 is 0.375. Then move the decimal point two places right: 37.5 percent.

Going the other way, a percent to a fraction: write it over 100 and simplify. 40 percent is 40 over 100, which is 2 over 5.

The ones that surprise people

Elle reads this

Three cases to meet now so they never surprise you later. 7.5 percent is 0.075: two places left, and the 7 slides past the decimal point. Half a percent is 0.005: half of one hundredth. 150 percent is 1.5, which is more than the whole thing, like a phone battery that could hold one and a half charges.

ElleMath-speak

A percent greater than 100 represents more than one whole.

FinnPlain English

More than 100 percent means more than all of it. 150 percent is the whole thing and half again.

Fill in the table

Finn reads this

Each row is one amount three ways. Fill in the blanks. Fractions can be typed like 3/4.

Let me try a few

NC standards: NC.7.RP.3, NC.7.EE.3.

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