Percentage

Concept 2

Each grid above has 100 boxes. For each grid, the ratio of the number of shaded boxes to the total number of boxes can be represented as a fraction.

Comparing Shaded Boxes to Total BoxesGrid Fraction Percentage

1 96%

2 9%

3 77%

Definition: A percent is a ratio whose second term is 100. Percent means parts per hundred. The word comes from the Latin phrase per centum, which means per hundred. In mathematics, we use the symbol % for percent

We can also show percents as decimals. Here’s how:

To change a percentage into a decimal, take up the % sign and divide by 100.

20%= .208%=.08Challenge: What would you do to change a

decimal to a percentage?

Multiply by 100 and attach a % sign.

Let's look at some examples in which we are asked to convert between, fractions, decimals and percents.

Fraction Decimal Percent

96/100 .96 96%

35/100 .35 35%

8/100 .08 8%

Your task: Write each fraction as a percent and as a decimal.

Extension:

Fraction Decimal Percent

5/100

80/100

2/100

17/100

Fraction Decimal Percent

2/50

30/50

45/50

5/10

25/100

3/20

Let’s try and convert them the other way:

Fraction Decimal Percent

.55

70%

85%

.03

17%

0.7