Year 9: Integer indices

This cheat-sheet covers integer indices. Indices represent how many times a number (the base) is multiplied by itself.

Key Concepts

  • Positive Integer Index: xn means x multiplied by itself n times (e.g., 23 = 2 * 2 * 2 = 8).
  • Negative Integer Index: x-n is the reciprocal of xn. (e.g., 2-2 = 1 / 22 = 1 / 4 = 0.25).
  • Zero Index: x0 = 1 (for any non-zero number x).

Rules

  • xm * xn = xm+n (Indices with the same base add)
  • xm / xn = xm-n (Indices with the same base subtract)
  • (xm)n = xm*n (Indices multiply)
  • x0 = 1

Examples

Example 1: Simplify 32 * 34 = 36 = 729

Example 2: Simplify x5 / x2 = x3

Example 3: Calculate (a2)3 = a6

Remember: Always simplify before calculating!