| Law | Rule | Example | In Words |
|---|---|---|---|
| Multiplication | aᵐ × aⁿ = aᵐ⁺ⁿ | 2³ × 2⁴ = 2⁷ | Add the powers |
| Division | aᵐ ÷ aⁿ = aᵐ⁻ⁿ | 5⁶ ÷ 5² = 5⁴ | Subtract the powers |
| Power of Power | (aᵐ)ⁿ = aᵐⁿ | (3²)⁴ = 3⁸ | Multiply the powers |
| Zero Power | a⁰ = 1 | 7⁰ = 1 | Any number to power 0 = 1 |
| Negative Power | a⁻ⁿ = 1/aⁿ | 2⁻³ = 1/8 | Negative power = reciprocal |
This key facts covers The Five Essential Index Laws within Index Laws for GCSE Mathematics. Revise Index Laws in Number for GCSE Mathematics with 14 exam-style questions and 22 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 3 of 14 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.
Practice questions for Index Laws
Which of these is equivalent to a³ × a⁵?
Simplify a⁵ × a³
Quick recall flashcards
Division Law
aᵐ ÷ aⁿ = aᵐ⁻ⁿ
SUBTRACT the powers
Example: 5⁶ ÷ 5² = 5⁴
Zero Power Law
a⁰ = 1
ANY number to power 0 equals 1
(except 0⁰ which is undefined)
Examples: 5⁰ = 1, 100⁰ = 1