1. 直接写出得数。
$\frac{3}{4}+\frac{3}{4}=$ $\frac{5}{8}-\frac{1}{8}=$ $\frac{5}{6}+\frac{1}{5}=$
$\frac{4}{5}+\frac{1}{5}=$ $\frac{4}{9}+\frac{2}{9}=$ $\frac{2}{3}-\frac{1}{6}=$
$\frac{9}{10}-\frac{7}{10}=$ $\frac{5}{7}+\frac{4}{7}=$ $\frac{3}{4}+\frac{1}{5}=$

$1\frac{1}{2}$
$\frac{1}{2}$
$1\frac{1}{30}$
1
$\frac{2}{3}$
$\frac{1}{2}$
$\frac{1}{5}$
$1\frac{2}{7}$
$\frac{19}{20}$

2. 把得数相同的式子连上线。
$\frac{1}{3}+\frac{1}{4}$ $\frac{5}{6}+\frac{2}{7}$ $\frac{3}{8}+\frac{1}{6}$ $\frac{5}{18}+\frac{14}{18}$
$\frac{5}{18}+\frac{7}{9}$ $\frac{9}{24}+\frac{4}{24}$ $\frac{35}{42}+\frac{12}{42}$ $\frac{4}{12}+\frac{3}{12}$

3. 计算。
$\frac{5}{7}+\frac{8}{21}$ $\frac{5}{6}-\frac{9}{14}$ $\frac{5}{8}-\frac{1}{6}$
$\frac{3}{4}+\frac{7}{20}$ $\frac{5}{6}+\frac{3}{8}$ $\frac{7}{12}-\frac{1}{5}$

$​=\frac {15}{21}+\frac {8}{21}​$
$​=\frac {23}{21}​$
$​=\frac {35}{42}-\frac {27}{42}​$
$​=\frac {4}{21}​$
$​=\frac {15}{24}-\frac {4}{24}​$
$​=\frac {11}{24}​$
$​=\frac {15}{20}+\frac {7}{20}​$
$​=\frac {11}{10}​$
$​=\frac {20}{24}+\frac {9}{24}​$
$​=\frac {29}{24}​$
$​=\frac {35}{60}-\frac {12}{60}​$
$​=\frac {23}{60}​$