一、口算。
$\frac {3}{5}×\frac {1}{3}=$
$\frac {20}{7}-2=$
$\frac {6}{25}×\frac {3}{4}=$
$\frac {8}{9}÷\frac {9}{8}=$
$\frac {1}{2}×\frac {1}{10}=$
$\frac {1}{4}+\frac {5}{12}=$
$28×\frac {1}{14}=$
$\frac {7}{9}÷\frac {7}{8}=$
$\frac {3}{8}÷\frac {3}{8}=$
$\frac {2}{15}-\frac {1}{10}=$
$\frac {3}{10}+\frac {7}{8}=$
$\frac {1}{2}×\frac {2}{3}=$
$\frac {2}{3}÷\frac {7}{6}=$
$\frac {1}{15}÷3=$
$\frac {3}{5}×\frac {8}{9}=$
$\frac {2}{9}÷\frac {3}{8}=$
$\frac {2}{3}-\frac {2}{5}=$
$\frac {1}{2}÷\frac {4}{5}=$
$\frac {1}{2}+\frac {1}{8}=$
$\frac {7}{15}÷\frac {7}{5}=$
$\frac {7}{12}×\frac {3}{14}=$

一、$\frac{1}{5}$ $\frac{6}{7}$ $\frac{9}{50}$ $\frac{64}{81}$ $\frac{1}{20}$ $\frac{2}{3}$ 2 $\frac{8}{9}$ 1 $\frac{1}{30}$ $\frac{47}{40}$ $\frac{1}{3}$ $\frac{4}{7}$ $\frac{1}{45}$ $\frac{8}{15}$ $\frac{16}{27}$ $\frac{4}{15}$ $\frac{5}{8}$ $\frac{5}{8}$ $\frac{1}{3}$ $\frac{1}{8}$

二、解方程。
$\frac {2}{3}x-\frac {2}{5}x= \frac {1}{3}$
$\frac {8}{9}+\frac {2}{3}x= 1$
$\frac {2}{7}x×\frac {5}{12}= \frac {5}{6}$
$\frac {6}{5}x-\frac {1}{5}= \frac {4}{15}$
$\frac {1}{4}x÷\frac {4}{9}= \frac {2}{5}$
$(x+\frac {3}{4})×\frac {2}{3}= \frac {3}{4}$

二、$x=\frac{5}{4}$ $x=\frac{1}{6}$ $x=7$ $x=\frac{7}{18}$ $x=\frac{32}{45}$ $x=\frac{3}{8}$

$\frac{2}{3}x - \frac{2}{5}x = \frac{1}{3}$
解：$\left(\frac{10}{15} - \frac{6}{15}\right)x = \frac{1}{3}$
$\frac{4}{15}x = \frac{1}{3}$
$x = \frac{1}{3} ÷ \frac{4}{15}$
$x = \frac{1}{3} × \frac{15}{4}$
$x = \frac{5}{4}$
$\frac{8}{9} + \frac{2}{3}x = 1$
解：$\frac{2}{3}x = 1 - \frac{8}{9}$
$\frac{2}{3}x = \frac{1}{9}$
$x = \frac{1}{9} ÷ \frac{2}{3}$
$x = \frac{1}{9} × \frac{3}{2}$
$x = \frac{1}{6}$
$\frac{2}{7}x × \frac{5}{12} = \frac{5}{6}$
解：$\frac{10}{84}x = \frac{5}{6}$
$\frac{5}{42}x = \frac{5}{6}$
$x = \frac{5}{6} ÷ \frac{5}{42}$
$x = \frac{5}{6} × \frac{42}{5}$
$x = 7$
$\frac{6}{5}x - \frac{1}{5} = \frac{4}{15}$
解：$\frac{6}{5}x = \frac{4}{15} + \frac{1}{5}$
$\frac{6}{5}x = \frac{4}{15} + \frac{3}{15}$
$\frac{6}{5}x = \frac{7}{15}$
$x = \frac{7}{15} ÷ \frac{6}{5}$
$x = \frac{7}{15} × \frac{5}{6}$
$x = \frac{7}{18}$
$\frac{1}{4}x ÷ \frac{4}{9} = \frac{2}{5}$
解：$\frac{1}{4}x = \frac{2}{5} × \frac{4}{9}$
$\frac{1}{4}x = \frac{8}{45}$
$x = \frac{8}{45} × 4$
$x = \frac{32}{45}$
$(x + \frac{3}{4}) × \frac{2}{3} = \frac{3}{4}$
解：$x + \frac{3}{4} = \frac{3}{4} ÷ \frac{2}{3}$
$x + \frac{3}{4} = \frac{3}{4} × \frac{3}{2}$
$x + \frac{3}{4} = \frac{9}{8}$
$x = \frac{9}{8} - \frac{3}{4}$
$x = \frac{9}{8} - \frac{6}{8}$
$x = \frac{3}{8}$