$1=3^0$
$3=3^1$
$9=3\ast 3=3^2$
$27=3\ast 3\ast 3=3^3$
$81=3\ast 3\ast 3\ast 3=3^4$
$\frac{1}{3}=3^{-1}$
$\frac{1}{9}=\frac{1}{3^2}=3^{-2}$
$\frac{1}{27}=\frac{1}{3^3}=3^{-3}$
$\frac{1}{81}=\frac{1}{3^4}=3^{-4}$

$1=(\frac{1}{3}{)}^0$
$3=(\frac{1}{3}{)}^{-1}$
$9=3^2=(\frac{1}{3}{)}^{-2}$
$27=3^3=(\frac{1}{3}{)}^{-3}$
$81=3^4=(\frac{1}{3}{)}^{-4}$
$\frac{1}{3}=(\frac{1}{3}{)}^1$
$\frac{1}{9}=\frac{1}{3^2}=(\frac{1}{3}{)}^2$
$\frac{1}{27}=\frac{1}{3^3}=(\frac{1}{3}{)}^3$
$\frac{1}{81}=\frac{1}{3^4}=(\frac{1}{3}{)}^4$