Fractions » Converting fractions into percentages

In order to calculate a percentage of a fraction, you multiply the fraction by one hundred. In most cases, you do not give a fraction in the answer, but you round to one decimal place. Calculate a percentage to a 'story exercise' is also the easiest with a fraction. See example 3.


In your calculations you write a per cent sign after the multiplication by one hundred. This is done because otherwise the two parts of your calculations are not equal. Then you would not be allowed to have the =- sign between the calculation and the answer. In the examples below you see, that you do write the red per cent sign but you do not key it in on your calculator. Of coure in your own calculation you do not write this per cent sign with a different colour.

Example 1

What percentage belongs to 38?
3 : 8 × 100% = 37.5%

Example 2

What percentage belongs to 13?
1 : 3 × 100% ≈ 33,3%

Example 3

If 3 of 25 cars are yellow, what percentage is that?
325 is yellow so 3 : 25 × 100% = 12%

You are using: numbertotal × 100% = ...%

See also percentages.