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GCSE Maths / Edexcel

Fractions, decimals, and percentages overview

Recognise which FDP skill a question is testing, then choose the right focused lesson for practice.

Number and Place ValueFoundation and HigherGrades 3 to 7Overview

Curriculum path: GCSE Maths > Edexcel > Number > Fractions, decimals, and percentages

Pearson Edexcel GCSE Maths number: use fractions, decimals, percentages, ratio, and proportional reasoning fluently.

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

Fractions, decimals, and percentages are three ways to show the same idea: part of a whole.

If the question asks you to simplify, compare, or make equivalent fractions, it is testing fraction structure.

If the question says a fraction of an amount, divide by the denominator first, then multiply by the numerator.

If the question asks for a percentage of an amount, convert the percentage to a decimal or build it from simple percentages such as 10%, 5%, and 1%.

If the question says increase or decrease by a percentage, use a percentage multiplier.

If the final amount is given after an increase or decrease and you need the original value, it is a reverse percentage question.

Use this page as the overview. For careful practice, use the separate FDP lessons in the Number and Place Value topic.

Key ruleRead the wording first: convert, fraction of amount, percentage of amount, percentage change, or reverse percentage.

Worked examples

Choosing the skill

Which skill is needed for: find 3 / 5 of 80?

  1. The phrase of 80 tells you this is an amount question.
  2. The fraction is 3 / 5, so divide by 5 first, then multiply by 3.
  3. The focused lesson is fractions of amounts.

Answer: Fractions of amounts

Percentage change clue

Which skill is needed for: decrease 120 by 15%?

  1. The word decrease tells you the original amount is being reduced.
  2. A 15% decrease leaves 85% of the original.
  3. The focused lesson is percentage increase and decrease.

Answer: Percentage decrease

Reverse percentage clue

A price after a 20% increase is 96. Which skill is needed?

  1. The final price after the increase is given.
  2. The question asks for the original price.
  3. That means this is a reverse percentage question.

Answer: Reverse percentages

Common mistakes

  • Trying to use one rule for every FDP question.
  • Confusing a percentage of an amount with percentage change.
  • Using the final value as the starting point in a reverse percentage question.
  • Forgetting to simplify fractions fully.
  • Mixing up decimal-to-percentage and percentage-to-decimal conversions.

Quick exercise

Try these before moving to the exam-style questions.

  1. Which skill converts 0.64 to 64%?
  2. Which skill finds 3 / 5 of 80?
  3. Which skill finds 35% of 80?
  4. Which skill increases 150 by 12%?
  5. Which skill finds the original value after a percentage change?
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-calculator3 marks

For each question, name the FDP skill being tested: (a) write 0.45 as a percentage, (b) find 2 / 3 of 90, (c) increase 80 by 15%.

fdp overviewexam languagefoundation number
Standard exam styleFoundation and HigherNon-calculator3 marks

Work out: (a) 3 / 5 of 80, (b) 35% of 80, (c) 0.35 as a fraction in its simplest form.

fractions of amountspercentages of amountsfdp conversions
ChallengeHigherCalculator4 marks

A jacket costs 64 after a 20% reduction. Explain why this is a reverse percentage question and find the original price.

reverse percentagespercentage decreasemultipliers