计算下面各题，怎样简便就怎样计算。
$236 + 180\div15 - 136$ $900 - 450\div18\times14$ $90\%\times32.4 + 32.4\div10$
$19.8 - 10.8\div4.5$ $(5 - 75\%-\frac{1}{4})\times\frac{3}{4}$ $2.7\times7.9 + 2.7\times2.1$
$\frac{3}{7}\div\frac{5}{6}+\frac{4}{7}\times\frac{6}{5}$ $(2 - \frac{1}{5}\div\frac{5}{9})\times\frac{5}{8}$ $1.25\times0.98\times0.8$
$\frac{3}{5}+\frac{7}{15}-\frac{3}{5}$ $\frac{7}{20}\div[\frac{1}{3}\times(\frac{5}{6}-\frac{7}{10})]$ $\frac{3}{8}\div[(\frac{1}{5}+\frac{1}{4})\times\frac{3}{8}]$
$(\frac{5}{9}+\frac{1}{23})\times9+\frac{14}{23}$ $\frac{9}{20}\div[(\frac{2}{5}+\frac{1}{3})\times\frac{3}{4}]$ $900\div(1 - 25\% - 30\%)$

112 550 32.4
17.4 3 27
$\frac{6}{5}$ $\frac{41}{40}$ 0.98
$\frac{7}{15}$ $\frac{63}{8}$ $\frac{20}{9}$
6 $\frac{9}{11}$ 2000