Answer
$\frac{1}{3}$
Work Step by Step
According to the product rule for exponents, $a^{m}\times a^{n}=a^{m+n}$ (where $m$ and $n$ are integers and $a$ is a real number).
Therefore, $3^{5}\times 3^{-6}=3^{5+(-6)}=3^{-1}$.
According to the definition of negative exponents, $a^{-n}=\frac{1}{a^{n}}$ (where $a\ne0$).
Therefore, $3^{-1}=\frac{1}{3^{1}}=\frac{1}{3}$.