How to decrease an amount by a percentage - BBC Bitesize (2024)

• An amount can be decreased by a in different ways:

  • By working out the decrease and subtracting it from the original value.

  • By considering the resulting overall percentage and using a .

• To be able to decrease an amount by a percentage, you need to be able to work out percentages of an amount, convert percentages to decimals and decimals to percentages.

• Identifying multipliers is a useful technique to use for this method. Processing calculations in one step can save time.

To decrease an amount by a given percentage:

1. Work out the percentage of the amount. There are different ways to do this, choose your preferred method:

a.Combining other percentages. For example, 20% is two lots of 10%

b.Using equivalent fractions. For example 20% is the same as 1⁄5

c.Using a calculator. For example to work out 20% divide 20 by 100 and multiply by the amount.

1. Subtract from the original amount.

To decrease an amount by a percentage using a :

1. The original amount is 100%.

2. Subtract the percentage the amount is being decreased by to get the remaining percentage.

3. Convert the remaining percentage value to a decimal by dividing by 100. This is the multiplier.

4. Multiply the original amount by the multiplier.

As part of a membership to a leisure centre, members are able to get a percentage discount at a sports shop. The price a member has to pay will be the original price decreased by a percentage. For example, if the discount is 20%, a pair of trainers priced at £90 will be £72 (100% – 20% = 90 – 18)

Healthy eating and drinking trends have led to many food companies reducing the sugar content in their products by a percentage. This enables them to produce healthier products and retain their sales.