FRACTIONS, DECIMALS AND PERCENTAGES

Subtracting Fractions

Learn the reliable method for subtracting fractions, then apply it to 11+ exam-style questions.

1 · WHAT YOU NEED TO KNOW

The idea

Fractions can only be added or subtracted directly when their denominators match.

Picture itCount equal parts of one whole
Bowls, fruit, scales and a measuring jug showing ratio and measurement in baking
2 · THE METHOD

Follow these steps

  1. Find a common denominator.
  2. Write equivalent fractions.
  3. Subtract the numerators and keep the denominator.
  4. Simplify the result.
3 · WORKED EXAMPLES

See the method in action

Example 1

A ribbon is 12/18 m long. A piece 4/11 m long is removed. What length remains?

  1. Use denominator 198: the result is 60/198, which simplifies to 10/33 m.
Answer: 10/33 m
Example 2

There is 2/5 km of rope available. After 1/7 km is used, the remainder is shared equally between two people. How much does each person receive?

  1. First use denominator 35: the initial result is 9/35 km.
  2. Half of 9/35 is 9/70 km.
Answer: 9/70 km
4 · ELEVENSPRINT TIP

A useful shortcut

The denominator names the part size, so do not add denominators.

5 · COMMON MISTAKES

Watch out for these

Adding the denominators

First make the part sizes equal; then operate on the numerators.

6 · TRY IT YOURSELF

Three fresh questions

Ready to check the method? You will get three fresh, validated questions.