This introduction covers What is Substitution? 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 8 of 19 in this topic. Use this introduction to connect the idea to the wider topic before moving on to questions and flashcards.
What is Substitution?
Think of a formula like a recipe. If a cake recipe says "2 × eggs + 100g flour", you substitute in the actual number of eggs to work out how much flour! Substitution in maths is the same - you replace the letters (variables) with actual numbers to calculate an answer.
Practice questions for Simplifying Expressions
Which two terms are like terms?
Explain why 3x + 2x² cannot be simplified to 5x³.
Quick recall flashcards
Substitution
Replace each letter with its given value, then calculate
Like Terms
Terms with same letter and power: 2x and 5x are like terms