Substitution and formulae · Grade 6
In Grade 6 you learn: substituting into simple formulas.
Substitution means replacing the letters in an expression or formula with numbers and working out the value. It is how formulas get used in real life — a taxi fare, a cooking time, or how far a ball rolls.
Key facts
- Then follow the order of operations: brackets, powers, × and ÷, then + and −.
- A fraction line acts like a bracket: work out the top and the bottom first.
- A formula such as A = lw links quantities; substitute what you know to find the one you don’t.