Calculating with Negative Indices

Calculating with Negative Indices

GCSE(F) GCSE(H)

A negative index indicates that the value is a reciprocal of the number: the number is written as a denominator and the numerator is set to 1.

For example, 2-2 can also be written as `frac(1)(2^2)` which evaluates to `frac(1)(4)`.

Examples

1. Calculate 42 ÷ 26.

Answer: `frac(1)(4)`

Rewrite the question as (22)2 ÷ 26.

Evaluate to 24 ÷ 26 = 2(4-6) = 2-2 = `frac(1)(2^2)` = `frac(1)(4)`

2. Calculate 52 ÷ 5-2.

Answer: 625

5(2 - -2) = 54.