$4a^4-16$

$\lim_{x\to2}\left(\frac{2x}{x-4}\right)$

$3\left(\frac{1}{2}m\right)\left(\frac{3}{5}n\right)^2$

$-\frac{3}{4}\left(-0.75\right)$

$3\left(\frac{-1}{3}+2\cdot\frac{4}{5}\right)\left(\frac{-1}{3}+\frac{4}{5}\right)$

$\frac{dy}{dx}=x+\left(y-x\right)\cdot\tan\left(x\right)$

$\frac{81x^4-1y^8}{16x^4+256y^8}$