1. 直接写出得数。
$ \frac{4}{5} - \frac{5}{7} = $$ $$ \frac{3}{4} + \frac{1}{2} = $$ $$ \frac{29}{30} - \frac{3}{10} = $$ $$ \frac{5}{14} - \frac{2}{7} + \frac{5}{7} = $
$ \frac{5}{6} + \frac{7}{10} = $$ $$ \frac{5}{6} + \frac{3}{8} = $$ $$ \frac{1}{4} + \frac{5}{6} = $$ $$ \frac{26}{17} - ( \frac{9}{17} + \frac{4}{15} ) = $
$ 1 - \frac{9}{11} = $$ $$ \frac{1}{8} - \frac{1}{9} = $$ $$ \frac{3}{4} - \frac{2}{5} = $$ $$ \frac{1}{5} + \frac{1}{4} - \frac{1}{20} = $
$ \frac{8}{9} - \frac{1}{6} = $$ $$ \frac{4}{7} + \frac{1}{4} = $$ $$ \frac{6}{7} + \frac{5}{6} = $$ $$ \frac{5}{9} - \frac{1}{2} + \frac{1}{6} = $
$ \frac{2}{5} + \frac{1}{15} = $$ $$ \frac{1}{9} + \frac{1}{6} = $$ $$ \frac{17}{18} - \frac{8}{9} = $$ $$ \frac{7}{8} - \frac{1}{4} + \frac{1}{8} = $
$ \frac{13}{6} - \frac{4}{5} = $$ $$ \frac{1}{2} + \frac{9}{16} = $$ $$ \frac{9}{10} + \frac{4}{5} = $$ $$ \frac{11}{2} - \frac{5}{6} - \frac{3}{5} = $

1. $\frac{3}{35}$ $\frac{5}{4}$ $\frac{2}{3}$ $\frac{11}{14}$
$\frac{23}{15}$ $\frac{29}{24}$ $\frac{13}{12}$ $\frac{11}{15}$
$\frac{2}{11}$ $\frac{1}{72}$ $\frac{7}{20}$ $\frac{2}{5}$
$\frac{13}{18}$ $\frac{23}{28}$ $\frac{71}{42}$ $\frac{2}{9}$
$\frac{7}{15}$ $\frac{5}{18}$ $\frac{1}{18}$ $\frac{3}{4}$
$\frac{41}{30}$ $\frac{17}{16}$ $\frac{17}{10}$ $\frac{61}{15}$

2. 计算下面各题，能简算的要简算。
$ \frac{2}{3} + \frac{5}{6} + \frac{4}{9} $$ $$ \frac{13}{15} - \frac{1}{3} - \frac{1}{5} $$ $$ \frac{8}{9} - ( \frac{1}{5} - \frac{1}{9} ) $
$ \frac{7}{10} - \frac{3}{7} + \frac{3}{7} - \frac{2}{5} $$ $$ \frac{5}{8} - \frac{3}{10} + \frac{1}{4} + \frac{7}{10} $$ $$ ( 8 \frac{1}{3} - 2 \frac{2}{5} ) - ( 3 \frac{1}{3} - 7.4 ) $

2. $\frac{35}{18}$ $\frac{1}{3}$ $\frac{4}{5}$
$\frac{3}{10}$ $\frac{51}{40}$ $10$

$3. $下面的计算对吗$？$对的画$“√”，$错的画$“×”，$并改正。　　

3. （1）× $5 - \frac{3}{5} + \frac{2}{5}$
$= \frac{22}{5} + \frac{2}{5}$
$= \frac{24}{5}$
（2）× $\frac{5}{6} + \frac{3}{8} + 1$
$= \frac{20}{24} + \frac{9}{24} + 1$
$= 2\frac{5}{24}$