This worksheet builds one of the most important skills in early algebra: substituting values into expressions and formulas to find an unknown. The worksheet is split into warm-up questions, standard questions and then extension questions to test you.
The concepts it covers:
- What a variable is — a letter (like x, a or n) standing in for a number that can change or is unknown
- What a formula is — a rule connecting variables, such as P = 4s for the perimeter of a square
- How to substitute — replacing a variable with its given value, then evaluating
- Why order of operations still matters — multiplication and division before addition and subtraction, even after substituting
- How implied multiplication works — that 2x means 2 × x, and ab means a × b
What your child will practise:
- Replacing each variable with its given value while keeping every operation the same
- Evaluating with the correct order of operations after substituting
- Applying substitution to real formulas — perimeter, area, speed and temperature conversion — to find an unknown
- Substituting negative values carefully and keeping track of signs
- Recognising implied multiplication: 2x, ab and 3(v − 1) all mean multiply
Every section opens with a worked example, and the download includes a full answer key with step-by-step solutions and teaching notes on the mistakes students most commonly make.
