一、口算。
$56×\frac {8}{7}=$
$\frac {4}{9}÷3=$
$\frac {4}{5}×\frac {5}{9}=$
$\frac {7}{10}÷\frac {2}{5}=$
$\frac {14}{15}×\frac {2}{7}=$
$\frac {2}{9}+\frac {1}{6}=$
$4×\frac {2}{3}=$
$\frac {1}{5}+\frac {3}{8}=$
$\frac {7}{10}-\frac {2}{15}=$
$\frac {5}{6}+\frac {1}{2}=$
$22÷\frac {11}{5}=$
$\frac {5}{12}÷\frac {1}{4}=$
$\frac {10}{21}×\frac {2}{5}=$
$3÷\frac {5}{7}=$
$21×\frac {5}{14}=$
$\frac {4}{5}-\frac {3}{4}=$
$\frac {7}{9}×\frac {15}{11}=$
$\frac {4}{9}÷36=$
$5÷\frac {15}{4}=$
$\frac {4}{9}÷\frac {9}{2}=$
$\frac {2}{9}×\frac {18}{7}=$

一、$64$ $\frac{4}{27}$ $\frac{4}{9}$ $\frac{7}{4}$ $\frac{4}{15}$ $\frac{7}{18}$ $\frac{8}{3}$ $\frac{23}{40}$ $\frac{17}{30}$ $\frac{4}{3}$ $10$ $\frac{5}{3}$ $\frac{4}{21}$ $\frac{21}{5}$ $\frac{15}{2}$ $\frac{1}{20}$ $\frac{35}{33}$ $\frac{1}{81}$ $\frac{4}{3}$ $\frac{8}{81}$ $\frac{4}{7}$

$56×\frac {8}{7}=64$
$\frac {4}{9}÷3=\frac{4}{27}$
$\frac {4}{5}×\frac {5}{9}=\frac{4}{9}$
$\frac {7}{10}÷\frac {2}{5}=\frac{7}{4}$
$\frac {14}{15}×\frac {2}{7}=\frac{4}{15}$
$\frac {2}{9}+\frac {1}{6}=\frac{7}{18}$
$4×\frac {2}{3}=\frac{8}{3}$
$\frac {1}{5}+\frac {3}{8}=\frac{23}{40}$
$\frac {7}{10}-\frac {2}{15}=\frac{17}{30}$
$\frac {5}{6}+\frac {1}{2}=\frac{4}{3}$
$22÷\frac {11}{5}=10$
$\frac {5}{12}÷\frac {1}{4}=\frac{5}{3}$
$\frac {10}{21}×\frac {2}{5}=\frac{4}{21}$
$3÷\frac {5}{7}=\frac{21}{5}$
$21×\frac {5}{14}=\frac{15}{2}$
$\frac {4}{5}-\frac {3}{4}=\frac{1}{20}$
$\frac {7}{9}×\frac {15}{11}=\frac{35}{33}$
$\frac {4}{9}÷36=\frac{1}{81}$
$5÷\frac {15}{4}=\frac{4}{3}$
$\frac {4}{9}÷\frac {9}{2}=\frac{8}{81}$
$\frac {2}{9}×\frac {18}{7}=\frac{4}{7}$

二、解方程。
$15+3x= 105$
$3x+4= 5.5$
$4x÷\frac {3}{5}= \frac {4}{15}$
$\frac {3}{5}x= \frac {1}{6}+\frac {4}{3}$
$\frac {3}{4}x×\frac {1}{4}= \frac {7}{12}$
$\frac {1}{3}x+\frac {8}{9}x= \frac {22}{3}$

二、$x=30$ $x=0.5$ $x=\frac{1}{25}$ $x=\frac{5}{2}$ $x=\frac{28}{9}$ $x=6$

解：15+3x=105
3x=105-15
3x=90
x=30
解：3x+4=5.5
3x=5.5-4
3x=1.5
x=0.5
解：4x÷$\frac{3}{5}$=$\frac{4}{15}$
4x=$\frac{4}{15}×\frac{3}{5}$
4x=$\frac{4}{25}$
x=$\frac{1}{25}$
解：$\frac{3}{5}x=\frac{1}{6}+\frac{4}{3}$
$\frac{3}{5}x=\frac{1}{6}+\frac{8}{6}$
$\frac{3}{5}x=\frac{9}{6}$
$\frac{3}{5}x=\frac{3}{2}$
x=$\frac{3}{2}×\frac{5}{3}$
x=$\frac{5}{2}$
解：$\frac{3}{4}x×\frac{1}{4}=\frac{7}{12}$
$\frac{3}{16}x=\frac{7}{12}$
x=$\frac{7}{12}×\frac{16}{3}$
x=$\frac{28}{9}$
解：$\frac{1}{3}x+\frac{8}{9}x=\frac{22}{3}$
$\frac{3}{9}x+\frac{8}{9}x=\frac{22}{3}$
$\frac{11}{9}x=\frac{22}{3}$
x=$\frac{22}{3}×\frac{9}{11}$
x=6