Grade five, CIE IGCSE Maths

Revision Notes

What is substitution?

Substitution is where we replace letters in a formula with their values.

This allows you to find one other value that is in the formula.

How do we substitute?

Write down the FORMULA if not clearly stated in question

  1. SUBSTITUTE the numbers given  – use ( ) around negative numbers
  2. SIMPLIFY if you can
  3. REARRANGE if necessary – it is usually easier to substitute first
  4. Do the CALCULATION – use a calculator if allowed


Substitution Example, IGCSE & GCSE Maths revision notes


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