How do you calculate percentage change?

Change

——————– x 100

Original value

How do you find the decimal multipliers for an increase?

Add the percentage to 100 then divide 100

1 . the percentage

How do you find the decimal multipliers for a decrease?

Take the percentage away from 100 then place 0 and a decimal

100% as a decimal multiplier?

TImes by 1

80% as a decimal multiplier?

0.8

Method 1 for working out the value before a percentage change:

The original price of a television is released by 30% in a sale. The sale price of the television is £350. Work out the normal price of the TV.

x = Value before percentage change

x X 0.7 = £350

x = 350/0.7 = £500

Where did I get the 0.7?

It’s what is left from 100 percentage

70% as a decimal multiplier

Method 2 for working out the value before a percentage change:

The original price of a television is released by 30% in a sale. The sale price of the television is £350. Work out the normal price of the TV.

70% = £350

You have 70% try and get 10% to find 100%

10% = £50

100% = £500