A percentage is a way of writing a fraction with a denominator of 100.
Percentage means "out of 100" or "per hundred"
Calculations involving percentages often require multiplication or division by 100.
x percent, written x%, means ^{x}⁄_{100} (or x parts out of 100)
Write 40% as a fraction |
40% = ^{40}⁄_{100} = ^{20}⁄_{50} = ^{10}⁄_{25} = ^{2}⁄_{5} |
Write the fraction ^{7}⁄_{10} as a percentage |
70% |
Percentage Calculations
Below are some of the types of problem that use percentages.
Percentage of a quantity:
To find x percent of a quantity. Calculate: ^{x}⁄_{100} × (the quantity)
Find 8% of 300 |
300 × ^{8}⁄_{100} = 24 |
One quantity as a percentage of another quantity:
To find a out of b as a percentage. Calculate: ^{a}⁄_{b} × ^{100}⁄_{1}
Write 13 out of 20 as a percentage. |
^{13}⁄_{20} × ^{100}⁄_{1} = 65% |
Increasing a quantity by a percentage:
To increase a quantity by x percent. Calculate:
Increase 50 by 8% |
Decreasing a quantity by a percentage:
To decrease a quantity by x percent. Calculate:
Decrease 50 by 8% |