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# What is a percentage?

By Lee Mansfield on the 11th of June, 2012

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Percent means "out of 100".

A percentage is a fraction expressed out of 100.

So 50% = 50/100 = 1/2 = one half

Percentages are used to compare how big numbers are compared with other numbers.

By Randy Warren on the 11th of June, 2012

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A percentage is the top part of a fraction whose bottom part is 100.
So 50% means 'half of' and 25% means 'a quarter of'. 100% means the complete quantity.

By Parvathy Neelakantan on the 16th of January, 2013

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In mathematics, a percentage is a number or ratio as a fraction of 100. It is often denoted using the percent sign, “%”,

For example, 30% (read as “thirty percent”) is equal to 30/100, or 0.3

Percentages are used to express how large/small one quantity is, relative to another quantity. The first quantity usually represents a part of, or a change in, the second quantity, which should be greater than zero. For example, an increase of \$ 0.15 on a price of \$ 2.50 is an increase by a fraction of 0.15/2.50 = 0.06. Expressed as a percentage, this is therefore a 6% increase.

By madhuchaliyan on the 17th of January, 2013

## Work out a percentage increase or decrease

### Percentage Increase or Decrease

In your GCSE Maths exam you will need to know how to work out a percentage increase or decrease multiple times! So, it is very important that you are comfortable with iworking out a percentage increase or decrease!

### Percentage Increase

Let’s say a shop owner needs to increase all their prices by 5%.

To do this, for each price they work out 5% of it, and then add it on.

Example: 5% of £200 is £10, so to increasing £200 by 5% gives £210.

With a calculator, a faster way of doing this is just to multiply £200 x 1.05 = £210

### Percentage Decrease

To perform a percentage decrease, simply subtract the 5%

Example: 5% of £200 is £10, so to decreasing £200 by 5% gives £190.

With a calculator, a faster way of doing this is just to multiply £200 x 0.95 = £190

## Follow the links below to see how this topic has appeared in past exam papers

AQA Unit 2 June 2011 (F) - Page 7, Question 10

AQA Unit 2 November 2010 (H) - Page 6, Question 8

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