Next, you will see how to convert the other way around; from fractions to percentages.
When you convert a fraction into a percentage, you can always do so via decimal numbers.
Let’s start with a simple example, . Remember that a fraction is a ratio between two quantities.
There are 25 girls in a group of 50 students. What percentage of the group are girls?
In the last step, we used the rule about moving the decimal mark two places to the right when converting from decimal numbers to percentages. You can also simply remember that .
Remember that you can change a fraction into a decimal number by either doing the division by hand, or by using a calculator. If the numbers are complicated, for example , it’s smart to use a calculator.
. You can convert this into a percentage by moving the decimal mark two places to the right.
You might prefer to find the percentage by creating an equation with an unknown . We’ll take a closer look at that later, but right now, let’s use the method shown in the example above.
In a class of 25 students, 15 of them are girls. What percentage of the class are girls?
15 out of 25 is a ratio between two quantities that can be expressed as the fraction . If you use a calculator, you get
You can also simplify the fraction and calculate 3 divided by 5, but you will get anyway. You then use the rule about moving decimal marks: .
The answer is that % of the class are girls.