一、口算。
$\frac{4}{5} × \frac{1}{2} =$
$\frac{3}{10} + \frac{1}{2} =$
$\frac{5}{6} × 0.7 =$
$\frac{7}{32} × 10 =$
$\frac{3}{2} - \frac{5}{6} =$
$\frac{11}{25} × \frac{10}{33} =$
$\frac{3}{4} - \frac{3}{5} =$
$\frac{2}{5} × 15 =$
$1.8 × \frac{2}{9} =$
$\frac{1}{6} × 2.4 =$
$\frac{17}{35} × \frac{5}{34} =$
$\frac{7}{9} × \frac{18}{11} =$
$\frac{3}{4} × \frac{8}{9} =$
$\frac{2}{3} + \frac{4}{5} =$
$\frac{8}{15} × \frac{5}{12} =$
$\frac{2}{3} × 0.75 =$
$\frac{4}{3} × \frac{12}{5} =$
$\frac{5}{18} × \frac{3}{4} =$
$\frac{2}{5} × \frac{1}{5} =$
$\frac{3}{7} - \frac{5}{28} =$
$\frac{7}{8} × \frac{11}{14} =$

1.$\frac{2}{5}$
2.$\frac{4}{5}$
3.$\frac{7}{12}$
4.$\frac{35}{16}$
5.$\frac{2}{3}$
6.$\frac{2}{15}$
7.$\frac{3}{20}$
8.$6$
9.$0.4$
10.$\frac{2}{3}$
11.$\frac{1}{14}$
12.$\frac{14}{11}$
13.$\frac{2}{3}$
14.$\frac{22}{15}$
15.$\frac{2}{9}$
16.$\frac{1}{2}$
17.$\frac{16}{5}$
18.$\frac{5}{24}$
19.$\frac{2}{25}$
20.$\frac{1}{4}$
21.$\frac{11}{16}$

二、写出下面各数的倒数。
9
$\frac{7}{11}$
$\frac{4}{3}$
$\frac{1}{8}$
$\frac{5}{7}$
$\frac{23}{6}$
1
0.2
$\frac{16}{17}$
$1\frac{3}{8}$

1.$\frac{1}{9}$
2.$\frac{11}{7}$
3.$\frac{3}{4}$
4.$8$
5.$\frac{7}{5}$
6.$\frac{6}{23}$
7.$1$
8.$5$
9.$\frac{17}{16}$
10.$\frac{8}{11}$