Yes, positive exponents go up top and negative exponents go on the bottom.
Typically when I start a problem like this I put all exponents as positive. For example
$\displaystyle \frac{r^8q^{-3}}{r^{-4}q^5}}$
I put this as
$\displaystyle \frac{r^8r^4}{q^3q^{5}}$
Then I simplify.
-Dan