Key Stage 3 Ratio and Proportion

Ratio Notation

Write, simplify and interpret ratios, including part-to-part and part-to-whole relationships.

Key idea

Find the multiplier or unit amount, then apply the same proportional change to the value you need.

What you will learn

Use ratio notation confidently.

Use simplifying ratios confidently.

Use sharing amounts confidently.

Use fractions and ratios confidently.

✓I can explain what ratio notation means.

✓I can choose a suitable method without being told.

✓I can show clear working and check my answer.

Worked example

Model method

Step 1

There are 3 + 5 = 8 parts.

Step 2

Each part is £40 ÷ 8 = £5.

Step 3

The shares are 3 × £5 and 5 × £5.

Answer

£15 and £25

Question 1

Share £60 in the ratio 2:3.

Question 2

5 pens cost £3. Find the cost of 12 pens.

Question 3

Increase £80 by 15%.

These are linked to the wider Ratio and Proportion topic for now.

A compact Ratio and Proportion summary with key facts, methods, reminders and common mistakes.

KS3 exam-style Ratio and Proportion questions with mixed practice, marks-style prompts and model answers.