This key facts covers Key Facts: Reverse Percentages within Reverse Percentages for GCSE Mathematics. Revise Reverse Percentages in Ratio & Proportion for GCSE Mathematics with 12 exam-style questions and 22 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 2 of 6 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
🔑 Key Facts: Reverse Percentages
- Reverse percentage = finding the original amount before a percentage change
- Key insight = the final amount represents a percentage of the original
- Method = divide the final amount by the multiplier
- Formula = Original amount = Final amount ÷ Multiplier
- Common scenarios: sale prices, after-tax amounts, final values after growth/decline
Practice questions for Reverse Percentages
A price after a 20% increase is £120. Which calculation finds the ORIGINAL price?
A TV costs £360 after a 10% increase. A student says: 'The original price was £360 - 10% = £360 - £36 = £324.' Explain the error in the student's method. What is the correct original price?
Quick recall flashcards
What is a reverse percentage?
Finding the original amount before a percentage change was applied
Give three examples of when you'd use reverse percentages
Finding original prices before sales, pre-tax amounts, original values before depreciation