How to help your child find fractions and percentages of amounts

Key Stage 2 fractions of amounts percentages of amounts

These are common questions that will pop up in tests and when your child is learning about fractions and percentages in more depth. It is useful to link these questions with real life scenarios, for example, when they are buying something in a sale with 15% off. This helps children to see how they can use their Numeracy skills in everyday life not just for a test!

Finding a fraction of an amount:

Children may start to come across this method in Year 4.

The top of a fraction is called the numerator and the bottom of the fraction is called the denominator.

The rule you need to use is: divide the whole number by the denominator and then multiply by the numerator.

e.g. Find ¾ of 8 = 8 (whole number) ÷ 4 (denominator) = 2 then 2 x 3 (numerator) = 6

Find 2/8 of 48 = 48 ÷ 8 = 6 then 6 x 2 = 12

Find 5/6 of £60 = £60 ÷ 6 = £10 then £10 x 5 = £50

Have a go at these with your child:

Find a 1/4 of 800, Find 3/4 of 200, Find 2/7 of 49, Find 3/6 of 36.

Finding a percentage of an amount:

Children will start to learn about percentages in Year 5. The basic rules with percentages are:

To find 10% = divide by 10

It is really important to reinforce with your child that this only works when finding 10% as often children think they can divide by 5 to find 5% or divide by 20 to find 20% etc.

To find 1% = divide by 100

Once you know these, you can find any percentage of an amount.

Some children find it easier to half the 10% amount to find 5%, others prefer to find the 1% amount and multiply this by 5.

For more help dividing by 10 and 100, check out this blog post.

 

Example 1: Find 10% of 200 – Rule divide by 10 = 200 ÷ 10 = 20

 

Example 2: Find 40% of 400 – Rule divide by 10 = 400 ÷ 10 = 40

Then, multiply the 10% amount by 4 to find 40% = 40 x 4 = 160. Therefore, 40% of 400 is 160.

 

Example 3: Find 26% of 300 – Rule: divide by 10 to find 10% (30), divide by 100 to find 1% (3)

Multiply the 10% amount by 2 to find 20% = 30 x 2 = 60. So 20% of 300 = 60

Multiply the 1% amount by 6 to find 6% = 3 x 6 = 18. Therefore, 6% of 300 = 18

Then, add the 20% and 6% amount together = 60 + 18 = 78. So 26% of 300 is 78.

 

Have a go at these with your child:

Find 10% of 360, Find 50% of 600, Find 5% of 800, Find 30% of 700, Find 55% of 500, Find 15% of 60, Find 23% of 200.

For more information on private tutoring to help your child in Numeracy and/or Literacy, please see the Private Tutoring page.

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