$4\cdot\frac{1}{2}\cdot1$

$\frac{1}{\frac{1}{r_{3}}+\frac{1}{r_{4}}+\frac{1}{r_{5}}+\frac{1}{r_{678}}}$

$\int\frac{x^2-2x-3}{\left(x-1\right)\left(x^2+2x+1\right)}dx$

$y'\:=20x-2$

$6+2\left(1+8\cdot22\right)-\left(1+\left(\sqrt{36}\right)\right)+164$

$n+4-n-2^2$

$\left(\frac{3}{2}a+b^2\right)^2$