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GCSE Maths / Edexcel

BIDMAS and order of operations

Use BIDMAS to decide the correct order in a calculation, including brackets, indices, multiplication, division, addition, and subtraction.

Number and Place ValueFoundationGrades 2 to 5Skill

Curriculum path: GCSE Maths > Edexcel > Number > BIDMAS and order of operations

Pearson Edexcel GCSE Maths number: apply the correct order of operations, including brackets and powers.

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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

BIDMAS is a memory aid for the order of operations: Brackets, Indices, Division and Multiplication, Addition and Subtraction.

Brackets are done first because they group part of the calculation together.

Indices means powers, such as 3². Work out powers before multiplying, dividing, adding, or subtracting.

Division and multiplication have the same priority. If both appear, work from left to right.

Addition and subtraction also have the same priority. If both appear, work from left to right.

A calculator follows order of operations, but Edexcel non-calculator questions test whether you can show the correct steps yourself.

Key ruleBIDMAS: Brackets, Indices, Division/Multiplication left to right, Addition/Subtraction left to right.

Worked examples

Multiplication before addition

Work out 6 + 4 x 3.

  1. There are no brackets or powers.
  2. Multiplication comes before addition, so work out 4 x 3 first.
  3. 4 x 3 = 12.
  4. 6 + 12 = 18.

Answer: 18

Brackets first

Work out (6 + 4) x 3.

  1. The brackets tell you to work out 6 + 4 first.
  2. 6 + 4 = 10.
  3. 10 x 3 = 30.

Answer: 30

Indices before multiplication

Work out 5 x 2² + 1.

  1. Work out the power first: 2² = 4.
  2. Then multiply: 5 x 4 = 20.
  3. Then add: 20 + 1 = 21.

Answer: 21

Common mistakes

  • Working strictly from left to right when multiplication should come before addition.
  • Adding before multiplying in calculations such as 6 + 4 x 3.
  • Forgetting that division and multiplication are equal priority, so they are done left to right.
  • Forgetting that addition and subtraction are equal priority, so they are done left to right.
  • Treating 3² as 3 x 2 instead of 3 x 3.

Quick exercise

Try these before moving to the exam-style questions.

  1. Work out 8 + 2 x 5.
  2. Work out (8 + 2) x 5.
  3. Work out 18 divided by 3 x 2.
  4. Work out 7 + 3².
  5. Work out 20 - 6 + 2.
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

Work out 9 + 5 x 4.

BIDMASmultiplication before additionorder of operations
Standard exam styleFoundationNon-calculator3 marks

Work out 3² + 4(7 - 2).

indicesbracketsBIDMAS
ChallengeFoundation and HigherNon-calculator4 marks

Insert brackets into 12 - 8 divided by 2 + 2 so that the answer is 4.

BIDMAS reasoningbracketsinverse thinking