MathLounge › Guides › Fractions

How to find a fraction of a number

Finding a fraction of a number means sharing the number into equal groups and taking some of them. To find 3/4 of 20, share 20 into 4 equal groups, then take 3 of the groups.

The short version: divide by the bottom number, then multiply by the top number.

Take the free fractions check Free, takes a few minutes, no sign-up.

Worked examples

3/4 of 20: 20 ÷ 4 = 5, then 5 × 3 = 15. So 3/4 of 20 = 15.
2/3 of 18: 18 ÷ 3 = 6, then 6 × 2 = 12.
5/8 of 40: 40 ÷ 8 = 5, then 5 × 5 = 25.

7 fraction of a number questions

1/2 of 16 = ?
1/3 of 21 = ?
3/4 of 12 = ?
2/5 of 25 = ?
5/6 of 30 = ?
3/8 of 24 = ?
7/10 of 50 = ?

Show answers

1/2 of 16 = 8
1/3 of 21 = 7
3/4 of 12 = 9
2/5 of 25 = 10
5/6 of 30 = 25
3/8 of 24 = 9
7/10 of 50 = 35

Tips for parents

Start with unit fractions (1/4 of 12) before fractions like 3/4.
Use counters or coins and actually share them out.
This skill depends on division facts, so a slow fact can look like a fraction problem.

Questions parents ask

How do you find a fraction of a number?

Divide the number by the denominator, then multiply by the numerator. For 3/4 of 20, divide 20 by 4 to get 5, then multiply by 3 to get 15.

Find out where your child is in a few minutes

Our free check shows which of 7 fraction skills are strong and which need work (grades 3 to 5). It runs in your browser, we don't ask for your child's name, and nothing your child types is saved.

Take the free fractions check

The check and its results are free. If you want a ready-made practice plan, the optional printable 4-week Fractions Fix-It Plan built from your child's results is $4.99, paid once, with a 30-day refund (see our Terms).