$\left(mn+n\right)^2$

$\lim_{x\to\frac{\pi}{2}}\left(\cos\left(x\right)\right)^{\left(\frac{\pi}{2}-x\right)}$

$5a^4-17-12$

$-4x^2-12x-9$

$\frac{y^{13}}{\left(y^2\right)^6}$

$2c+\left(-\frac{10}{c}\right)+1,\:c=-2$

$\left(-34\right)\:-\:\left(+24\right)\:-\:\left(-13\right)\:-\:\left(+45\right)\:+\:\left(+50\right)\:-\:\left(-32\right)\:+\:\left(-27\right)\:-\:\left(-20\right)\:+\:\left(+36\right)\:$