Definition
Percentage of a quantity
The amount found by multiplying a quantity by a stated percent, written as a fraction or decimal.
What it means
A percent tells you how many hundredths to take. Write the percent as a fraction over 100 or as a decimal, then multiply by the whole quantity. This finds the chosen share of that quantity.
Remember it
The percent sign means “out of 100”: take that share of the whole quantity.
Example
A box holds 80 beads. To find 15% of 80, calculate 0.15 × 80 = 12. The percentage of the quantity is 12 beads.
Watch for
The percent is the rate; the percentage of the quantity is the amount produced. In the example, 15% is the rate and 12 beads is the amount.
Common mix-up
Do not multiply by 15. Since 15% means 15/100, multiply by 0.15 instead.
Exact meaning
For a percent p and quantity q, p% of q is (p/100) × q. The result has the same unit as q when q measures something.