一、直接写出得数。
$\frac{3}{7}÷ 7= $
$\frac{1}{3}× 9× \frac{2}{3}= $
$\frac{5}{8}× \frac{2}{3}= $
$\frac{5}{6}× (18+\frac{6}{25})= $
$\frac{1}{6}× 12= $
$\frac{2}{9}÷ \frac{3}{5}= $
$(3\frac{1}{8}+\frac{7}{9})× 0= $
$\frac{1}{2}+\frac{7}{12}= $
$\frac{1}{6}+\frac{1}{7}= $
$\frac{1}{6}-\frac{1}{7}= $
$\frac{4}{5}+\frac{5}{4}= $
$\frac{7}{12}× 13= $
$\frac{3}{7}÷ 7= $
$\frac{3}{49}$
$\frac{1}{3}× 9× \frac{2}{3}= $
2
$\frac{5}{8}× \frac{2}{3}= $
$\frac{5}{12}$
$\frac{5}{6}× (18+\frac{6}{25})= $
$\frac{76}{5}$
$\frac{1}{6}× 12= $
2
$\frac{2}{9}÷ \frac{3}{5}= $
$\frac{10}{27}$
$(3\frac{1}{8}+\frac{7}{9})× 0= $
0
$\frac{1}{2}+\frac{7}{12}= $
$\frac{13}{12}$
$\frac{1}{6}+\frac{1}{7}= $
$\frac{13}{42}$
$\frac{1}{6}-\frac{1}{7}= $
$\frac{1}{42}$
$\frac{4}{5}+\frac{5}{4}= $
$\frac{41}{20}$
$\frac{7}{12}× 13= $
$\frac{91}{12}$
答案
解析：
这些题目主要考查分数的四则运算，包括分数的乘法、除法、加法和减法。其中涉及带分数与假分数的转换，以及分数与整数的混合运算。
答案：
$\frac{3}{7} ÷ 7 = \frac{3}{7}×\frac{1}{7}=\frac{3}{49}$
$\frac{1}{3} × 9 × \frac{2}{3} = 3 × \frac{2}{3} = 2$
$\frac{5}{8} × \frac{2}{3} = \frac{5}{12}$
$\frac{5}{6} × (18 + \frac{6}{25}) = \frac{5}{6}×( \frac{450}{25} + \frac{6}{25}) =\frac{5}{6} × \frac{456}{25} = \frac{5 × 456}{6 × 25} = \frac{2280}{150} = \frac{76}{5} = 15.2$
$\frac{1}{6} × 12 = 2$
$\frac{2}{9} ÷ \frac{3}{5} = \frac{2}{9} × \frac{5}{3} = \frac{10}{27}$
$(3\frac{1}{8} + \frac{7}{9}) × 0 = 0$
$\frac{1}{2} + \frac{7}{12} = \frac{6}{12} + \frac{7}{12} = \frac{13}{12}$
$\frac{1}{6} + \frac{1}{7} = \frac{7}{42} + \frac{6}{42} = \frac{13}{42}$
$\frac{1}{6} - \frac{1}{7} = \frac{7}{42} - \frac{6}{42} = \frac{1}{42}$
$\frac{4}{5} + \frac{5}{4} = \frac{16}{20} + \frac{25}{20} = \frac{41}{20}$
$\frac{7}{12} × 13 = \frac{7 × 13}{12} = \frac{91}{12}=7\frac{7}{12}$
这些题目主要考查分数的四则运算，包括分数的乘法、除法、加法和减法。其中涉及带分数与假分数的转换，以及分数与整数的混合运算。
答案：
$\frac{3}{7} ÷ 7 = \frac{3}{7}×\frac{1}{7}=\frac{3}{49}$
$\frac{1}{3} × 9 × \frac{2}{3} = 3 × \frac{2}{3} = 2$
$\frac{5}{8} × \frac{2}{3} = \frac{5}{12}$
$\frac{5}{6} × (18 + \frac{6}{25}) = \frac{5}{6}×( \frac{450}{25} + \frac{6}{25}) =\frac{5}{6} × \frac{456}{25} = \frac{5 × 456}{6 × 25} = \frac{2280}{150} = \frac{76}{5} = 15.2$
$\frac{1}{6} × 12 = 2$
$\frac{2}{9} ÷ \frac{3}{5} = \frac{2}{9} × \frac{5}{3} = \frac{10}{27}$
$(3\frac{1}{8} + \frac{7}{9}) × 0 = 0$
$\frac{1}{2} + \frac{7}{12} = \frac{6}{12} + \frac{7}{12} = \frac{13}{12}$
$\frac{1}{6} + \frac{1}{7} = \frac{7}{42} + \frac{6}{42} = \frac{13}{42}$
$\frac{1}{6} - \frac{1}{7} = \frac{7}{42} - \frac{6}{42} = \frac{1}{42}$
$\frac{4}{5} + \frac{5}{4} = \frac{16}{20} + \frac{25}{20} = \frac{41}{20}$
$\frac{7}{12} × 13 = \frac{7 × 13}{12} = \frac{91}{12}=7\frac{7}{12}$
二、怎样简便就怎样算。
$\frac{8}{13}÷ 7+\frac{1}{7}× \frac{6}{13}$
$\frac{1}{2}× \frac{2}{5}+\frac{9}{10}÷ \frac{9}{20}$
$(\frac{1}{2}+\frac{2}{3}+\frac{3}{4})× 24$
$\frac{2}{9}+\frac{1}{2}÷ \frac{4}{5}+\frac{3}{8}$
$17× \frac{7}{18}$
$\frac{4}{7}× 20+\frac{4}{7}$
$\frac{8}{13}÷ 7+\frac{1}{7}× \frac{6}{13}$
$\frac{1}{2}× \frac{2}{5}+\frac{9}{10}÷ \frac{9}{20}$
$(\frac{1}{2}+\frac{2}{3}+\frac{3}{4})× 24$
$\frac{2}{9}+\frac{1}{2}÷ \frac{4}{5}+\frac{3}{8}$
$17× \frac{7}{18}$
$\frac{4}{7}× 20+\frac{4}{7}$
答案
$\frac{8}{13}÷ 7+\frac{1}{7}× \frac{6}{13}$
$=\frac{8}{13}×\frac{1}{7}+\frac{1}{7}×\frac{6}{13}$
$=(\frac{8}{13}+\frac{6}{13})×\frac{1}{7}$
$=\frac{14}{13}×\frac{1}{7}$
$=\frac{2}{13}$
$\frac{1}{2}× \frac{2}{5}+\frac{9}{10}÷ \frac{9}{20}$
$=\frac{1}{5}+\frac{9}{10}×\frac{20}{9}$
$=\frac{1}{5}+2$
$=2\frac{1}{5}$
$(\frac{1}{2}+\frac{2}{3}+\frac{3}{4})× 24$
$=\frac{1}{2}×24+\frac{2}{3}×24+\frac{3}{4}×24$
$=12 + 16 + 18$
$=46$
$\frac{2}{9}+\frac{1}{2}÷ \frac{4}{5}+\frac{3}{8}$
$=\frac{2}{9}+\frac{1}{2}×\frac{5}{4}+\frac{3}{8}$
$=\frac{2}{9}+\frac{5}{8}+\frac{3}{8}$
$=\frac{2}{9}+(\frac{5}{8}+\frac{3}{8})$
$=\frac{2}{9}+1$
$=1\frac{2}{9}$
$17× \frac{7}{18}$
$=(18 - 1)×\frac{7}{18}$
$=18×\frac{7}{18}-1×\frac{7}{18}$
$=7 - \frac{7}{18}$
$=6\frac{11}{18}$
$\frac{4}{7}× 20+\frac{4}{7}$
$=\frac{4}{7}×(20 + 1)$
$=\frac{4}{7}×21$
$=12$
$=\frac{8}{13}×\frac{1}{7}+\frac{1}{7}×\frac{6}{13}$
$=(\frac{8}{13}+\frac{6}{13})×\frac{1}{7}$
$=\frac{14}{13}×\frac{1}{7}$
$=\frac{2}{13}$
$\frac{1}{2}× \frac{2}{5}+\frac{9}{10}÷ \frac{9}{20}$
$=\frac{1}{5}+\frac{9}{10}×\frac{20}{9}$
$=\frac{1}{5}+2$
$=2\frac{1}{5}$
$(\frac{1}{2}+\frac{2}{3}+\frac{3}{4})× 24$
$=\frac{1}{2}×24+\frac{2}{3}×24+\frac{3}{4}×24$
$=12 + 16 + 18$
$=46$
$\frac{2}{9}+\frac{1}{2}÷ \frac{4}{5}+\frac{3}{8}$
$=\frac{2}{9}+\frac{1}{2}×\frac{5}{4}+\frac{3}{8}$
$=\frac{2}{9}+\frac{5}{8}+\frac{3}{8}$
$=\frac{2}{9}+(\frac{5}{8}+\frac{3}{8})$
$=\frac{2}{9}+1$
$=1\frac{2}{9}$
$17× \frac{7}{18}$
$=(18 - 1)×\frac{7}{18}$
$=18×\frac{7}{18}-1×\frac{7}{18}$
$=7 - \frac{7}{18}$
$=6\frac{11}{18}$
$\frac{4}{7}× 20+\frac{4}{7}$
$=\frac{4}{7}×(20 + 1)$
$=\frac{4}{7}×21$
$=12$
