# Percentage

## What is a percentage?

Percentage is a part of something. 1 percent is one hundredth of the whole.

Percent is usually denoted with %, but it can also be written as a fraction or a decimal number.

For example, 4% can be written as:

Percent is central to specify the rate of interest, tax and VAT.

## Typical mathematical problems concerning percentage

1. What is 25% of $1100? First you calculate 1% of$1100. We need to divide by 100.

Then you calculate 25% by multiplying the result by 25.

So 25% of $1100 is$275.
Instead of doing this calculation in two steps you can make one calculation given by:

2. What is the initial value, when 20% of the initial value is 25?
First you divide 25 by 20 and find 1 % of the initial value:

Now you just need multiply the result by 100 in order to find 100% (the whole) of the initial value:

So the initial value is 125, if 20% of it is 25.
Given as one expression the calculation look like this:

3. How do you express the relationship between 1600 and 800 in percent?
First you calculate the relationship between 1600 and 800:

Since 0.50 is the same as 50%, 800 is 50% of 1600.

4. How much is 190 greater than 120, in percent?
First you find the different between the numbers:

Then you find the relationship between the smaller number and the difference between the numbers calculated above:

So 190 is 58.33% greater than 120.

5. How much is 120 smaller than 190?
First you find the different between the numbers:

Then you find the relationship between the greater number and the difference between the numbers calculated above:

So 120 is 36.84% smaller than 190.

## Procentage calculator

 Number 1: Number 2: Percent:

## Per mille

Per mille or per thousand is divisions of thousandth. It is denoted with ‰. 1 percent is equal to 10 per thousand, so it’s often used to specify very small amounts of something.

4‰ can also be written as: