Expressing one amount as a fraction of another Revision Card

AI generatedNumberKS3 / GCSE

Decide which amount is being compared with which. The reference amount goes on the bottom.

Decide which amount is being compared with which. The reference amount goes on the bottom.
Convert both amounts into the same units before making a fraction.
Simplify using a common factor. The fraction may be greater than 1.

Example 1

Express 10 cm as a fraction of 50 cm.

Both measurements are already in centimetres.

Divide numerator and denominator by 10.

Express 60 cm as a fraction of 90 cm.

Both measurements are already in centimetres.

Divide numerator and denominator by 15.

Remember
Use the worked steps to check your method, not just the final answer.

Question 1

Express 120 cm as a fraction of 140 cm.

Check answer

Both measurements are already in centimetres.

Divide numerator and denominator by 20.

Question 2

Express 175 cm as a fraction of 200 cm.

Check answer

Both measurements are already in centimetres.

Divide numerator and denominator by 25.

Question 3

Express 210 cm as a fraction of 270 cm.

Check answer

Both measurements are already in centimetres.

Divide numerator and denominator by 30.

Question 4

Express 210 cm as a fraction of 350 cm.

Check answer

Both measurements are already in centimetres.

Divide numerator and denominator by 35.

Question 5

Express 160 cm as a fraction of 440 cm.

Check answer

Both measurements are already in centimetres.

Divide numerator and denominator by 40.