Percentages of Amounts
Finding percentages of amounts is one of the most practical maths skills students learn. This includes calculating discounts, tax, tips, pay rises, and other real-world percentage applications that appear heavily in exam contexts.
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No questions match the current filters for Percentages of Amounts.
What You'll Learn
- Calculating a percentage of an amount using multipliers
- Finding the original amount after a percentage increase or decrease
- Calculating percentage profit and loss
- Comparing quantities using percentage difference
Watch Out For These Mistakes
Students make these errors again and again. Knowing them in advance gives you a head start.
Calculating the percentage and then forgetting to add or subtract it from the original
Dividing by the new amount instead of the original in reverse percentage problems
Using additive methods that break down for large percentage changes
What Examiners Say About Percentages of Amounts
Insights pulled from Cambridge IGCSE (0580) examiner reports — the exact mistakes candidates make every year.
- Common Mistake●●●●●
For train-crossing-bridge problems: (1) Total distance = train length + bridge length, (2) Convert all units to be consistent (all metres + seconds, or all km + hours) BEFORE calculating.
Source: CIE 0580 · Feb/March 2024 · Paper 2 · Q14
- Common Mistake●●●●●
If 5/13 are sold, then 8/13 remain. Set the remainder (96) equal to the remaining fraction (8/13 of total), not the sold fraction. A decimal answer in a whole-number context should alert you to an err
Source: CIE 0580 · Feb/March 2021 · Paper 1 · Q13
- Misconception●●●●●
Percentage profit = (profit / COST PRICE) × 100 — divide by COST, not selling price. Profit = selling − cost. This is the most-missed type of percentage question.
Source: CIE 0580 · May/June 2021 · Paper 3 · Q1f(i)
Based on 3of 500+ insights extracted from CIE 0580 examiner reports (2018–2024).
Exam Coverage
This topic appears in the Cambridge IGCSE past papers. Our AI tutor can help with it on any question.
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Ratio, proportion, and percentage formulae