Calculating the percentage of something is necessary if you want to find out of the proportions between two quantities. Some percentage calculations are easy and can be done without any helping tools, while others are more complex and may require a calculator. Calculators have a percentage button so you will not need to know any special formulas to calculate percentage. However, in some tests you can only use pen and paper, so it is important to learn some percentage calculating formulas.

Calculate the percentage of something by multiplying the full value by the percentage you want to get. Divide the result by 100. For example, if you want to get 12 per cent of 9500, multiply 9500 by 12 and divide the result by 100.

Divide the percentage by 100 and multiply it by the full value. For example, if you want to get 12 per cent of 9500, divide 12 by 100, which is .12, and multiply it by 9500.

Add a percentage to the full value by multiplying the full value by 1 plus the percentage fraction. For example, if you want to add 9 per cent to 9500, multiply 9500 by 1.09.

Subtract a percentage from the full value by multiplying the full value by 100 minus the percentage you want to subtract. For example, to deduct 9 per cent from 9500, multiply 9500 by .91.

Calculate 10 per cent by dividing the full value by 10. To get multiples, such as 30, 40 or 60 per cent, divide the full value by 10 and multiply the result by 3, 4, 6 and so on.

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Calculate 50 per cent by dividing the full value by 2. Calculate 33 per cent of something by dividing the full value by 3. Calculate 25 per cent of something by dividing the full value by 4.