PlosMathLearning

Percentages

Percentages



A percentage is a special type of fraction with 100 as the denominator. Percentage is indicated by the symbol %.


How to write a percentage as a fraction

To write a percentage as a fraction you write using 100 as the denominator.

Example: 35% is written as 35100.


How to change a fractions as a percentage

To change a fraction to a percentage you multiply by 100.

Example: 25 written as a percentage = 25 × 100 = 40%


How to change a decimal to a percentage

To change a decimal to a percentage you multiply by 100.

Example: 0.63 = 0.63 × 100 = 63%


How to write a percentage as a decimal

To write a percentage as a decimal you must divide by 100.

Example: 35% = 35100 = 0.35


Percentage Calculation

Example: Find 35% of 200.

35% of 200 means 35% × 200

= 35100 × 200

= 70


How to express one quantity as a percentage of another

Example Express 54 as a percentage of 60.

= 5460 × 100 = 90%


Finding percentage increase

percentage increase = increaseoriginal amount × 100

Example: The number of students in a grade 10 class was increased from 20 to 25. Find the percentage increase.

Solution

original amount = 20

increase = 25 - 20 = 5

% increase = 520 × 100 = 25%



Copyright © 2012 Peter Smith

All Rights Reserved.

Important Information