$\frac{8^3}{8^2}$

$-2\left[-6+5\:\cdot\:\left(-4-2\right)\right]$

$\:-16\:-\:\:-25\:-\:\left[-34\:+\:\left(-26\:-\:-45\right)\:-\:\left(-12\:-23\right)\:\right]\:-15\:$

$\int_2^3\left(\frac{x-1}{\sqrt{4x-x^2}}\right)dx$

$-\left(\left(3.6+4\right)\cdot\left(1.8\cdot\left(-5.1+3.9\right)\right)\right)$

$\frac{12x^{3}+28x^{2}+11x-6}{2x+3}$

$x-2^2-x+1\cdot x-3$