The Method: Reverse BIDMAS

Part of Rearranging Formulae · Section 2 of 6

Deep DiveUnit: AlgebraGCSE

This deep dive covers The Method: Reverse BIDMAS within Rearranging Formulae for GCSE Mathematics. Revise Rearranging Formulae in Algebra for GCSE Mathematics with 14 exam-style questions and 11 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 2 of 6 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.

The Method: Reverse BIDMAS

1 Identify what you want to make the subject
2 Do the OPPOSITE operations in REVERSE order
3 Whatever you do to one side, do to the other

Order to undo: Addition/Subtraction first → Multiplication/Division → Powers/Roots

Practice questions for Rearranging Formulae

Make b the subject of the formula: a = b + c

  • A. b = a + c
  • B. b = c − a
  • C. b = a − c
  • D. b = ac
1 markfoundation

The circumference of a circle is given by the formula: C = 2πr Make r the subject of the formula.

2 marksfoundation

Quick recall flashcards

What does 'rearranging a formula' produce?
An equivalent formula expressing a different variable as the subject. E.g. v = u + at rearranges to a = (v − u)/t.
What is the 'subject' of a formula?
The variable that stands alone on one side of the equals sign. In v = u + at, v is the subject.

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