Ratio & ProportionExam Tips

Common Mistakes to Avoid

Part of Direct Proportion · GCSE GCSE Mathematics revision

This exam tips covers Common Mistakes to Avoid within Direct Proportion for GCSE Mathematics. Revise Direct Proportion in Ratio & Proportion for GCSE Mathematics with 15 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 8 of 9 in this topic. Treat this as a marking guide for what examiners are looking for, not just a fact list.

Topic position

Section 8 of 9

Practice

15 questions

Recall

12 flashcards

Common Mistakes to Avoid

X Confusing direct and inverse proportion Direct: both go up together. Inverse: one up, one down. Check: does doubling x DOUBLE y or HALVE y?

X Forgetting the graph passes through (0,0) Direct proportion ALWAYS passes through origin If x = 0, then y = k × 0 = 0

Keep building this topic

Read this section alongside the surrounding pages in Direct Proportion. That gives you the full topic sequence instead of a single isolated revision point.

Worked Example 3: Best Buy Problem Knowledge Organiser: Direct Proportion What is Direct Proportion?Key Features of Direct Proportion

Practice Questions for Direct Proportion

Which of the following correctly reads the mathematical statement y ∝ x?

A. y is inversely proportional to x
B. y is directly proportional to x
C. y equals x
D. y is greater than x

1 markfoundation

Explain what it means for y to be directly proportional to x. Your answer should refer to the equation and the graph.

2 marksstandard

Quick Recall Flashcards

What does the graph of y = kx look like?

A straight line passing through the origin (0, 0). The gradient of the line equals k. If the line does NOT pass through (0,0), it is NOT direct proportion.

What does the symbol ∝ mean?

'is proportional to' y ∝ x means 'y is proportional to x' This is equivalent to writing y = kx for some constant k.

15 questions on Direct Proportion — practise free

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Worked Example 3: Best Buy Problem

Knowledge Organiser: Direct Proportion