1 直接写出得数。(每题1分,共20分)
$\frac {4}{7}-\frac {1}{2}= $ $\frac {1}{4}+\frac {3}{8}= $ $\frac {1}{8}+\frac {5}{8}= $ $\frac {9}{10}-\frac {3}{10}= $
$\frac {2}{7}+\frac {1}{14}= $ $\frac {3}{10}+\frac {4}{5}= $ $\frac {8}{9}-\frac {2}{9}= $ $\frac {3}{4}+\frac {1}{2}= $
$\frac {3}{4}+\frac {1}{6}= $ $\frac {7}{10}-\frac {3}{10}= $ $\frac {3}{16}+\frac {1}{2}= $ $7-\frac {3}{7}-\frac {4}{7}= $
$\frac {1}{3}-\frac {1}{4}= $ $\frac {1}{2}+\frac {1}{3}= $ $\frac {5}{18}-\frac {1}{6}= $ $1\frac {3}{8}-\frac {3}{8}= $
$\frac {10}{10}-\frac {9}{9}= $ $1-\frac {1}{5}= $ $\frac {15}{14}-\frac {4}{7}= $ $\frac {7}{8}-\frac {1}{20}+\frac {1}{8}= $

$\frac{1}{14}$ $\frac{5}{8}$ $\frac{3}{4}$ $\frac{3}{5}$
$\frac{5}{14}$ $\frac{11}{10}$ $\frac{2}{3}$ $\frac{5}{4}$
$\frac{11}{12}$ $\frac{2}{5}$ $\frac{11}{16}$ 6
$\frac{1}{12}$ $\frac{5}{6}$ $\frac{1}{9}$ 1
0 $\frac{4}{5}$ $\frac{1}{2}$ $\frac{19}{20}$

2 计算下列各题,能简算的要简算。(每题3分,共18分)
$5-\frac {4}{9}-\frac {5}{9}$ $\frac {4}{5}+\frac {11}{15}+\frac {3}{10}$ $\frac {2}{7}+\frac {1}{6}+\frac {5}{6}+\frac {7}{7}$
$\frac {8}{15}-(\frac {8}{15}-\frac {7}{18})$ $\frac {3}{7}+\frac {3}{4}-\frac {11}{14}$ $\frac {13}{15}-(\frac {13}{15}-\frac {2}{5})$

4 $\frac{11}{6}$ 2
$\frac{7}{18}$ $\frac{11}{28}$ $\frac{2}{5}$

3 解方程。(每题4分,共12分)
$x-(\frac {3}{14}+\frac {4}{7})= \frac {1}{2}$ $x-\frac {4}{5}= \frac {1}{4}$ $\frac {1}{6}+x= \frac {7}{2}$

解：$x=\frac{9}{7}$ 解：$x=\frac{21}{20}$ 解：$x=\frac{10}{3}$