Pearson Edexcel International GCSE in Mathematics (Specification A) · 4MA1 · Free · no account needed
Percentages
The most-asked number topic: multipliers, percentage change, reverse percentages and compound interest — appearing on almost every paper, fumbled on almost every paper.
Every lesson here ends the same way: learn it, teach it to an AI pupil who asks the awkward question, then defend it against the thinker with the strongest claim on it — free · no account needed.
3 modules of Pearson Edexcel International GCSE Mathematics, each explained in full — what it is, why it works, when a question is asking for it, the mistakes that cost marks and worked examples — with five graded questions marked on your own device. Completely free.
The modules in Percentages
Percentage Basics
What 'per cent' actually means, finding a percentage of an amount, and writing one number as a percentage of another. 'Per cent' is Latin for 'per hundred' — 35% IS the number 0.35.
When a question is asking for it: Test scores, discounts, interest, statistics — and as the entry point to every harder percentage skill. Learn Percentage Basics →
Multipliers & Percentage Change
The multiplier method — one number that does the whole job — for increases, decreases, repeated change and 'what was the overall change?' Every percentage change is captured by one multiplier: +15% is ×1.15, −24% is ×0.76.
When a question is asking for it: 'Increase/decrease … by …%' → build the multiplier. Learn Multipliers & Percentage Change →
Reverse Percentages & Compound Interest
Finding the original price before a change (the question everyone gets backwards), and money growing multiplier-on-multiplier. A reverse percentage question gives you the value AFTER a change and asks for the original: 'a coat costs £44 after 20% off'.
When a question is asking for it: Watch for AFTER-words: 'sale price', 'after the increase', 'now worth', 'including VAT'. Learn Reverse Percentages & Compound Interest →
The mistakes that cost marks in Percentages
One from each module — the error examiners see most, with the module that puts it right.
- Dividing by the percentage: 35% of 480 is not 480 ÷ 35. 'Of' means multiply — by the decimal 0.35. (Percentage Basics)
- Measuring change against the NEW value. Percentage change always divides by the ORIGINAL. (Multipliers & Percentage Change)
- Adding the percentage back: £44 + 20% of £44 = £52.80 ≠ £55. The 20% was 20% of the ORIGINAL (£55), a bigger number. (Reverse Percentages & Compound Interest)
Where Percentages sits in the specification
Content area 1 of 4MA1, sub-topic 1.6. Incandio is aligned to the specification and is not published by Pearson; the numbers are given so you can check every module against your own copy.
- 1.6 — Percentages — reverse percentage, compound interest
How Percentages is mastered on Incandio
Every module above ends the same way: five questions that climb Grade 6 → 9+, then you teach the method back to Ember, an AI pupil who asks the awkward question, and defend it against the mathematician with the strongest claim on it. Exam Ready carries 31 authored exam-style questions across this strand, marked on Incandio.
All of Incandio Mathematics · The 4MA1 specification · Exam Ready