一、口算。
$\frac{8}{9} ÷ \frac{3}{4} =$
$\frac{2}{9} ÷ \frac{7}{9} =$
$\frac{1}{6} ÷ 3 =$
$\frac{15}{24} ÷ \frac{5}{12} =$
$\frac{7}{5} ÷ \frac{3}{4} =$
$\frac{3}{2} ÷ \frac{2}{5} =$
$\frac{1}{3} ÷ \frac{5}{12} =$
$\frac{11}{7} ÷ \frac{11}{4} =$
$\frac{5}{9} ÷ \frac{2}{3} =$
$\frac{1}{3} ÷ \frac{5}{6} =$
$\frac{5}{8} ÷ \frac{1}{3} =$
$27 ÷ \frac{9}{4} =$
$\frac{1}{6} ÷ \frac{1}{7} =$
$\frac{9}{2} ÷ \frac{3}{8} =$
$\frac{11}{18} ÷ \frac{22}{9} =$
$\frac{7}{9} ÷ \frac{14}{3} =$
$\frac{5}{7} ÷ \frac{7}{5} =$
$\frac{4}{5} ÷ \frac{5}{8} =$
$7 ÷ \frac{21}{2} =$
$\frac{5}{11} ÷ \frac{9}{22} =$
$\frac{3}{20} ÷ \frac{6}{7} =$

1.$\frac{32}{27}$ 2.$\frac{2}{7}$ 3.$\frac{1}{18}$ 4.$\frac{3}{2}$ 5.$\frac{28}{15}$ 6.$\frac{15}{4}$ 7.$\frac{4}{5}$ 8.$\frac{4}{7}$ 9.$\frac{5}{6}$ 10.$\frac{2}{5}$ 11.$\frac{15}{8}$ 12.$12$ 13.$\frac{7}{6}$ 14.$12$ 15.$\frac{1}{4}$ 16.$\frac{1}{6}$ 17.$\frac{25}{49}$ 18.$\frac{32}{25}$ 19.$\frac{2}{3}$ 20.$\frac{10}{9}$ 21.$\frac{7}{40}$

二、计算下面各题，能用简便算法的就用简便算法。
$(12 - \frac{2}{5}) ÷ \frac{2}{15}$
$\frac{4}{13} ÷ \frac{3}{7} + \frac{9}{13} ÷ \frac{3}{7}$
$\frac{4}{7} × [ \frac{5}{3} ÷ (1 + \frac{1}{9}) ]$
$\frac{21}{32} ÷ ( \frac{1}{8} + \frac{3}{4} )$
$\frac{5}{14} ÷ 7 + 7 ÷ \frac{7}{8}$
$\frac{9}{10} ÷ \frac{26}{27} - \frac{9}{10} ÷ 26$

1.$87$ 2.$\frac{7}{3}$ 3.$\frac{6}{7}$ 4.$\frac{3}{4}$ 5.$8\frac{5}{98}$ 6.$\frac{9}{10}$