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# How do I work out a percentage decrease?

By Lisa Kelly on the 11th of June, 2012

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Work out the percentage of your number and then subtract it.

Example

Decrease 90 by 20%.

20% of 90 is 18 (since 90x20/100=18)

So our answer is given by 90-18=72.

By Lee Mansfield on the 13th of June, 2012

## 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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