1
Write out the expression
Copy it exactly as given
2
Replace each letter with its value
Use brackets around the number, especially for negatives!
3
Follow BIDMAS to calculate
Brackets, Indices, Division/Multiplication, Addition/Subtraction
4
Write your final answer
Check it makes sense!
This deep dive covers Method: How to Substitute within Simplifying Expressions for GCSE Mathematics. Revise Simplifying Expressions in Algebra for GCSE Mathematics with 11 exam-style questions and 5 flashcards. Use this page as part of a wider topic revision path rather than treating it as an isolated fact. It is section 9 of 19 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Simplifying Expressions
Which two terms are like terms?
Explain why 3x + 2x² cannot be simplified to 5x³.
Quick recall flashcards
Like Terms
Terms with same letter and power: 2x and 5x are like terms
Substitution
Replace each letter with its given value, then calculate