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GCSE Maths / Edexcel

Percentages of amounts

Find a percentage of an amount using simple percentages or by converting the percentage to a decimal.

Number and Place ValueFoundation and HigherGrades 3 to 5Focused skill

Curriculum path: GCSE Maths > Edexcel > Number > Percentages > Percentages of amounts

Pearson Edexcel GCSE Maths number: calculate percentages of quantities.

Practise this topicUpload your answerAsk AI to explain thisTry exam-style questions
Revision notes

Theory, examples, and quick checks.

Keep the method short, then practise straight away. This note is written for GCSE Maths Edexcel students who need clear working and reliable method marks.

Theory

A percentage of an amount means a part out of 100 of that amount.

10% means one tenth, so divide by 10.

5% is half of 10%. 1% is one hundredth, so divide by 100.

For non-calculator questions, build percentages from easy parts. For example, 35% = 30% + 5%.

For calculator questions, change the percentage to a decimal and multiply by the amount.

For example, 35% of 80 can be done as 0.35 x 80.

Key rulePercentage of an amount: convert the percentage, then multiply by the amount.

Worked examples

Find 10%

Find 10% of 240.

  1. 10% means divide by 10.
  2. 240 / 10 = 24.

Answer: 24

Build from simple percentages

Find 35% of 80.

  1. 10% of 80 = 8.
  2. 30% of 80 = 24.
  3. 5% of 80 = 4.
  4. 35% = 30% + 5%, so 24 + 4 = 28.

Answer: 28

Decimal multiplier

Find 18% of 250.

  1. 18% = 0.18.
  2. 0.18 x 250 = 45.

Answer: 45

Common mistakes

  • Dividing by the percentage instead of finding the percentage of the amount.
  • Finding 10% correctly but forgetting to build the required percentage.
  • Using 0.35 for 3.5% or 0.035 for 35%.
  • Confusing percentage of an amount with percentage increase.

Quick exercise

Try these before moving to the exam-style questions.

  1. Find 10% of 90.
  2. Find 5% of 90.
  3. Find 20% of 70.
  4. Find 35% of 80.
  5. Find 18% of 250.
Exam-style questions

Practise the same skill at three levels.

These are original GCSE-style questions with mark schemes, common wrong answers, and AI marking guidance so feedback stays close to exam expectations.

Basic GCSE styleFoundationNon-calculator2 marks

Find 15% of 60.

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Standard exam styleFoundation and HigherCalculator3 marks

A phone costs 320 pounds. A case costs 12.5% of the phone price. Find the cost of the case.

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ChallengeHigherCalculator4 marks

A school has 1240 students. 37% travel by bus. Estimate how many students travel by bus and explain your estimate.

percentages of amountsestimationworded problem