Math - Percentage

Percentage is a number expressed as a fraction (or ratio) of 100.

Percentage Formulas

• The percentage of a value:
  $\frac{\text{value}}{\text{total}} \times 100$

• The value of a percentage:
  $\frac{\text{percentage}}{100} \times \text{value}$

• The percentage increase and decrease:
  $\frac{new - old}{old} \times 100$

Examples

$\frac{4}{10} \times 10 = 40\%$
$\frac{31}{100} \times 572 = 177.32$
$\frac{150 - 75}{75} \times 100 = +50\%$