Percentage is way of expressing the fraction of a whole in terms of
parts per
hundred.
Percentage is from the Latin
per centum which means per hundred.
50% means 50 parts per 100.
| (fraction) | 50 | = | 0.50 (decimal) × 100% = 50% (percentage) |
| 100 |
Any fraction can be expressed as a percentage or a decimal.
| (fraction) | 1 | = | 0.50 (decimal) × 100% = 50% (percentage) |
| 2 |
To calculate the
decimal from a
fraction, divide the numerator by the denominator.
To calculate the
percentage from the
decimal multiply
by 100%.
If the percentage of A is known and the total is known the number of A in a sample can be calculated.
| 25% A = | number of A | × 100% |
| 88 |
Convert the percentage to a decimal by dividing by 100%. Multiply both sides of the equation by 88.
This is known as cross-multiplying
(the denominator of one side of the equation is multiplied by the numerator of the other).number of A = 0.25 × 88 = 22