Indices (or exponents) represent repeated multiplication. Base: number being multiplied; Index: how many times multiplied. Notation: a^n = a×a×...×a (n times). Key concepts: a^0 = 1 (any number to power 0); a^1 = a (any number to power 1). Rules: a^m × a^n = a^(m+n); a^m ÷ a^n = a^(m-n); a^(-n) = 1/a^n; a^(1/n) = nth root. Example: 2^5 = 32; 2^(-3) = 1/8; 2^(1/2) = √2. Shortcut: Use law of indices to simplify before calculating. Exam tip: Always identify base and index correctly. Negative and fractional indices appear frequently in exams.