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GCSE Percentages Revision Guide
Mastering percentages is essential for GCSE success. This guide covers everything from basic percentage of amounts to complex compound interest and reverse calculations.
Foundation
Higher Tier
Exam Practice
Formulae
Topic Overview
Percentages represent a fraction of 100. In the GCSE curriculum, you'll be tested on your ability to convert between fractions, decimals, and percentages, as well as applying these to real-world scenarios like finance, statistics, and geometric changes. This module provides a structured path from basic concepts to Grade 9 level problems.
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Lessons
Worked Examples
Practice Hub
Video Lessons
Essential Percentage Formulas
Percentage Change
(Change ÷ Original) × 100
New Amount (Multiplier)
Original × (1 ± %/100)
Compound Change
Original × (1 ± r/100)^n
Lesson Modules
Compound Interest
Calculate growth over time using exponential multipliers. Essential for Higher tier.
Percentage Decrease
Mastering depreciation and sales discounts using 1-step multipliers.
Percentage Increase
Learn how to apply mark-ups and interest rates effortlessly.
Percentage of an Amount
The fundamentals: using mental math and calculators for basic find-it-all.
Reverse Percentages
Working backwards to find the original amount after a change.
Core Subtopics
Structured lessons for every syllabus requirement.
Worked Example
Step-by-Step Worked Example
Topic: Reverse Percentages
THE QUESTION
A jacket is sold for £54 in a 10% off sale. What was its original price?
Method
- Identify that 100% – 10% = 90%
- The sale price (£54) is 90% of the original price.
- Divide by 0.9 (the multiplier for 90%)
- Original Price = £54 ÷ 0.9
Common Mistake
Don't calculate 10% of £54 and add it on. This will give you £59.40, which is incorrect!
Final Answer
£60.00
Practice Resources
Revision Worksheet
20 carefully graded questions for all levels.
Topic Quiz
Timed 15-minute challenge with instant feedback.
Exam Questions
Real past paper questions from AQA & Edexcel.
Mark Scheme
Check your work with expert guidance.
Playlist
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Expert Video Tutorials
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Frequently Asked Questions
How do I turn a decimal into a percentage?
Multiply the decimal by 100. For example, 0.45 × 100 = 45%. If you’re going the other way, just divide by 100!
Is "percentage multiplier" used for all questions?
Multipliers are best for calculator papers. For non-calculator papers, you might find it easier to find 10%, then 5%, and add them up.
What's the difference between simple and compound interest?
Simple interest is calculated only on the original amount. Compound interest is calculated on the original amount plus any interest that has been added previously.
