wunder beta🔢 Substituting Values into Formulas
Replace letters with numbers — including negatives — and evaluate expressions and science formulas using the correct order of operations.
1
lesson
~15 min
to learn
🔢 Math
subject
Ages 6–12
level
What you’ll learn
- Substituting into FormulaeSubstitute numerical values — including negatives and powers — into expressions and scientific formulas, evaluating with the correct order of operations.Substitution replaces each letter with a given value, then evaluates using BIDMAS (brackets, indices, division/multiplication, addition/subtraction). Evaluating 2a + 3 at a = 4 gives 11. Negatives need care: for 5 − 2x with x = −3, use brackets — 5 − 2 × (−3) = 5 + 6 = 11. Powers come before multiplication, so 2 + 3n² at n = 2 is 2 + 3 × 4 = 14. The same steps power science formulas, such as speed = distance ÷ time giving 100 ÷ 20 = 5 m/s.
Questions this course answers
Evaluate 5 − 2x when x = −3.
2 × (−3) = −6, and 5 − (−6) = 5 + 6 = 11.
When substituting a negative number, why is it wise to use brackets?
Brackets keep the minus sign with its number so operations stay correct.
Evaluate 2 + 3n² when n = 2.
Power first: 2² = 4, then 3 × 4 = 12, then 2 + 12 = 14.
What does 'substituting into a formula' mean?
Substitution swaps letters for their values, then evaluates.
Grounded in trusted sources
- BBC Bitesize — Maths (Key Stage 3)
- Khan Academy — Evaluating expressions
- NRICH (University of Cambridge)
- Britannica
Every Wunder lesson is built from real, reputable sources — never invented.
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