$\frac{80.4\sin20}{\sin25}$

$3^{14}+5^2$

$2-6+20-10-15+40-30-20+70$

$5x+\left\{-\left(3x-x-y\right)\right\}\cdot8x+\left\{-2x-x+y\right\}$

$\lim_{x\to1}\left(x^5-x^4+6x^3-6x^2+x-1\right)$

$\frac{8a^3-44a^2+44a+42}{4a^2-8a-6}$

$5^{-3}\cdot25^{-3}\cdot\left(5^{-1}\right)^{-3}$