三、计算下面各题，怎样简便就怎样计算。（最后一题4分，其余每题3分，共37分）
$16\times75 - 624\div39$ $\frac{5}{6}-(\frac{1}{5}+\frac{1}{3})\div\frac{8}{9}$ $3.25\times1.8 + 67.5\times0.18$
$1.25\times3.2\times0.25$ $\frac{5}{4}\times\frac{5}{11}+\frac{6}{11}\div\frac{4}{5}$ $21\times(\frac{1}{21}+\frac{1}{15})\times15$
$4.5\times101$ $\frac{7}{9}\times\frac{15}{16}+\frac{17}{16}\times\frac{7}{9}$ $\frac{6}{7}\div[(\frac{6}{7}-37.5\%)\times\frac{8}{9}]$
$\frac{5}{12}\div(\frac{3}{2}-\frac{6}{7}-\frac{1}{7})$ $7.1\times3.42 + 2.9\times3.42$ $\frac{4}{7}\times[87.5\%\div(\frac{5}{6}-75\%)]$

1184 $\frac{7}{30}$ 18
1 $\frac{5}{4}$ 36
454.5 $\frac{14}{9}$ 2
$\frac{5}{6}$ 34.2 6