$$\frac{4^{m}\times15^{4m-2n+1}\times9^{n-2m}}{10^{2m}\times25^{m-n}}$$
$\frac{4^{m}\times 9^{n-2m}\times 25^{n-m}\times 15^{4m-2n+1}}{10^{2m}}$
$0$
