Evaluate 3^-1-2

$3^{- 1} - 2$

Rewrite the expression using the negative exponent rule $b^{- n} = \frac{1}{b^{n}}$ .

$\frac{1}{3} - 2$

To write $- 2$ as a fraction with a common denominator, multiply by $\frac{3}{3}$ .

$\frac{1}{3} - 2 \cdot \frac{3}{3}$

Combine $- 2$ and $\frac{3}{3}$ .

$\frac{1}{3} + \frac{- 2 \cdot 3}{3}$

Combine the numerators over the common denominator.

$\frac{1 - 2 \cdot 3}{3}$

Simplify the numerator.

Multiply $- 2$ by $3$ .

$\frac{1 - 6}{3}$

Subtract $6$ from $1$ .

$\frac{- 5}{3}$

Move the negative in front of the fraction.

$- \frac{5}{3}$

The result can be shown in multiple forms.

Exact Form:

$- \frac{5}{3}$

Decimal Form:

$- 1.\overline{6}$

Mixed Number Form:

$- 1 \frac{2}{3}$