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!