一、口算。
$\frac{5}{12} ÷ \frac{15}{16} =$
$\frac{4}{13} ÷ \frac{1}{3} =$
$\frac{2}{15} ÷ \frac{8}{35} =$
$\frac{4}{9} ÷ \frac{4}{3} =$
$\frac{5}{8} ÷ 2 =$
$\frac{7}{12} ÷ 7 =$
$\frac{5}{24} ÷ \frac{5}{12} =$
$\frac{5}{48} ÷ \frac{1}{4} =$
$\frac{14}{15} ÷ \frac{7}{30} =$
$\frac{7}{11} ÷ \frac{7}{9} =$
$\frac{3}{10} ÷ \frac{6}{5} =$
$\frac{3}{7} ÷ \frac{5}{21} =$
$\frac{5}{12} ÷ 5 =$
$\frac{5}{8} ÷ \frac{5}{16} =$
$\frac{2}{15} ÷ \frac{6}{5} =$
$10 ÷ \frac{1}{15} =$
$\frac{3}{8} ÷ \frac{3}{10} =$
$\frac{5}{8} ÷ \frac{5}{2} =$
$\frac{8}{9} ÷ \frac{5}{18} =$
$\frac{1}{5} ÷ \frac{3}{4} =$
$\frac{3}{10} ÷ \frac{3}{8} =$

1.$\frac{4}{9}$
2.$\frac{12}{13}$
3.$\frac{7}{12}$
4.$\frac{1}{3}$
5.$\frac{5}{16}$
6.$\frac{1}{12}$
7.$\frac{1}{2}$
8.$\frac{5}{12}$
9.$4$
10.$\frac{9}{11}$
11.$\frac{1}{4}$
12.$\frac{9}{5}$
13.$\frac{1}{12}$
14.$2$
15.$\frac{1}{9}$
16.$150$
17.$\frac{5}{4}$
18.$\frac{1}{4}$
19.$\frac{16}{5}$
20.$\frac{4}{15}$
21.$\frac{4}{5}$

二、计算下面各题，能用简便算法的就用简便算法。
$18÷\frac{3}{7}÷\frac{14}{3}$
$\frac{8}{15}÷9+\frac{1}{9}×\frac{7}{15}$
$(\frac{7}{18}+\frac{5}{24})÷\frac{1}{72}$
$\frac{3}{40}÷0.2×\frac{2}{3}$
$6÷\frac{1}{2}-\frac{1}{2}÷6$
$5-\frac{14}{75}÷\frac{2}{15}-\frac{3}{5}$

1.$9$
2.$\frac{1}{9}$
3.$43$
4.$\frac{1}{4}$
5.$11\frac{11}{12}$
6.$3$