# Percent

Percent means "for each hundred". It is a way to show how big a fraction of a quantity we mean. For example if we say "twenty percent of students in the school have brown eyes", we read that to mean "For each hundred students, twenty students have brown eyes".

It is written with a special symbol: %

So for example 'twenty percent' is written as 20%.

If you look at the symbol, it does look a bit like the number 100, The 'one' leans over and the two '0's make up the 100.

Try this Drag the two orange dots to see how a percentage is calculated:

## Percentage

The word 'percentage' is used when we are asking for the number. So, for example, we can ask "What percentage of students have brown eyes?". The answer would be "twenty percent". Written as 20%.

## It's really just a fraction

Percentages are really just another way to write a fraction.

If we say "50 percent of these pencils are blue" we mean that for every 100 pencils, 50 are blue. This is half the pencils. (half 100 is 50). So we can also say "half these pencils are blue". We can convert a percentage to a fraction simply by writing it as the percent over 100: By dividing the top and bottom by 5: So we can say that 5% is the same as "one twentieth". So for example if 5% of cars are red, all the following statements are true:

• 5% of all cars are red
• 5 cars in every hundred are red
• One car in twenty is red
• One twentieth of all cars are red.

A percentage can be also written as a decimal. For example 5%: Enter the 5 in a calculator and divide it by 100:

## Converting percent to a fraction

To convert a percentage to a fraction, put the percentage over 100. For example

## Converting a fraction to a percentage

To convert a fraction to a percentage multiply the fraction by 100. For example, converting one fifth: This can be reduced by dividing top and bottom by 5:

## Calculating percentages

In the example: "10% of 50 cars = 5 cars", we have three numbers involved:
1. The starting number. (50 cars)
2. The percentage. (10%)
3. The result. (5 cars)

We can find any one of them if we know the other two.

The three cases are described in Calculating percentages.

## Things to try

• In the applet at the top of the page, click "hide details". Then adjust the slider left and right and try to estimate what percentage of the total it is. Click "show details" to check your estimate.
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