一、口算。
$\frac {7}{30}×60=$ $\frac {5}{8}÷\frac {3}{8}=$ $\frac {7}{8}-\frac {5}{24}=$
$\frac {4}{5}÷\frac {2}{7}=$ $7×\frac {3}{14}=$ $\frac {3}{7}÷6=$
$\frac {2}{3}÷\frac {8}{5}=$ $\frac {3}{4}+\frac {3}{16}=$ $\frac {4}{5}-\frac {1}{3}=$
$\frac {3}{7}-\frac {1}{14}=$ $\frac {3}{10}+\frac {1}{4}=$ $\frac {3}{10}÷\frac {3}{5}=$
$\frac {4}{5}×\frac {1}{4}=$ $\frac {3}{4}÷\frac {1}{2}=$ $\frac {7}{8}×\frac {4}{7}=$
$27÷\frac {3}{8}=$ $\frac {2}{3}+\frac {3}{4}=$ $\frac {4}{5}÷\frac {4}{3}=$
$\frac {2}{9}×\frac {3}{8}=$ $\frac {5}{3}÷\frac {5}{4}=$ $\frac {5}{12}×\frac {8}{5}=$

一、14 $\frac {5}{3}$ $\frac {2}{3}$
$\frac {14}{5}$ $\frac {3}{2}$ $\frac {1}{14}$
$\frac {5}{12}$ $\frac {15}{16}$ $\frac {7}{15}$
$\frac {5}{14}$ $\frac {11}{20}$ $\frac {1}{2}$
$\frac {1}{5}$ $\frac {3}{2}$ $\frac {1}{2}$
72 $\frac {17}{12}$ $\frac {3}{5}$
$\frac {1}{12}$ $\frac {4}{3}$ $\frac {2}{3}$

二、先化简下面各比,再求比值。
$15:\frac {10}{9}$ $\frac {3}{5}:\frac {25}{12}$ 1.5米：20分米
$11:12.1$ $0.35:\frac {7}{10}$ 250毫升：$\frac {5}{4}$升

二、$27:2$ $36:125$ $3:4$
$\frac {27}{2}$ $\frac {36}{125}$ $\frac {3}{4}$
$10:11$ $1:2$ $1:5$
$\frac {10}{11}$ $\frac {1}{2}$ $\frac {1}{5}$