1. 计算下面各题。
$26×\frac{5}{39}$
$\frac{24}{35}×\frac{21}{20}$
$\frac{15}{16}×\frac{4}{3}×\frac{8}{5}$
$9÷\frac{6}{13}×\frac{4}{39}$
$\frac{3}{5}÷6×\frac{10}{9}$
$\frac{7}{8}÷\frac{21}{25}÷\frac{5}{16}$
$26×\frac{5}{39}$
$\frac{24}{35}×\frac{21}{20}$
$\frac{15}{16}×\frac{4}{3}×\frac{8}{5}$
$9÷\frac{6}{13}×\frac{4}{39}$
$\frac{3}{5}÷6×\frac{10}{9}$
$\frac{7}{8}÷\frac{21}{25}÷\frac{5}{16}$
答案：$ =\frac {6×3}{5×5}$
$ =\frac {18}{25}$
$ =\frac {2×5}3$
$ =\frac {10}3$
$ =\frac 54×\frac 85$
=2
$ =9×\frac {13}6×\frac 4{39}$
$ =9×(\frac {13}6×\frac 4{39})$
$ =9×\frac 29$
=2
$ =\frac 35×\frac 16×\frac {10}9$
$ =\frac 1{10}×\frac {10}9$
$ =\frac 19$
$ =\frac 78×\frac {25}{21}×\frac {16}5$
$ =\frac {25}{24}×\frac {16}5$
$ =\frac {10}3$
$ =\frac {18}{25}$
$ =\frac {2×5}3$
$ =\frac {10}3$
$ =\frac 54×\frac 85$
=2
$ =9×\frac {13}6×\frac 4{39}$
$ =9×(\frac {13}6×\frac 4{39})$
$ =9×\frac 29$
=2
$ =\frac 35×\frac 16×\frac {10}9$
$ =\frac 1{10}×\frac {10}9$
$ =\frac 19$
$ =\frac 78×\frac {25}{21}×\frac {16}5$
$ =\frac {25}{24}×\frac {16}5$
$ =\frac {10}3$
2. 下面各题,怎样算简便就怎样算。
$\frac{7}{12}×\frac{4}{5}+\frac{11}{5}×\frac{7}{12}$
$(21+\frac{7}{12})÷\frac{7}{3}$
$\frac{32}{33}×34$
$[1-(\frac{3}{4}-\frac{2}{5})]×\frac{25}{26}$
$\frac{2}{3}+\frac{5}{18}×\frac{4}{5}+\frac{7}{9}$
$(\frac{1}{6}-\frac{1}{7})÷\frac{1}{42}$
$\frac{2}{7}÷(\frac{8}{9}×\frac{2}{7})÷\frac{8}{9}$
$[\frac{7}{11}-(\frac{8}{15}-\frac{4}{11})]÷\frac{14}{45}$
$\frac{7}{12}×\frac{4}{5}+\frac{11}{5}×\frac{7}{12}$
$(21+\frac{7}{12})÷\frac{7}{3}$
$\frac{32}{33}×34$
$[1-(\frac{3}{4}-\frac{2}{5})]×\frac{25}{26}$
$\frac{2}{3}+\frac{5}{18}×\frac{4}{5}+\frac{7}{9}$
$(\frac{1}{6}-\frac{1}{7})÷\frac{1}{42}$
$\frac{2}{7}÷(\frac{8}{9}×\frac{2}{7})÷\frac{8}{9}$
$[\frac{7}{11}-(\frac{8}{15}-\frac{4}{11})]÷\frac{14}{45}$
答案：$ =(\frac 45+\frac {11}5)×\frac 7{12}$
$ =3×\frac 7{12}$
$ =\frac 74$
$ =(21+\frac 7{12})×\frac 37$
$ =21×\frac 37+\frac 7{12}×\frac 37$
$ =9+\frac 14$
$ =9\frac 14$
$ =\frac {32}{33}×(33+1)$
$ =\frac {32}{33}×33+\frac {32}{33}$
$ =32+\frac {32}{33}$
$ =32\frac {32}{33}$
$ =[1-\frac 7{20}]×\frac {25}{26}$
$ =\frac {13}{20}×\frac {25}{26}$
$ =\frac 58$
$ =\frac 23+\frac 29+\frac 79$
$ =\frac 23+(\frac 29+\frac 79)$
$ =1\frac 23$
$ =(\frac 16-\frac 17)×42$
$ =\frac 16×42-\frac 17×42$
=7-6
=1
$ =\frac 27÷\frac 27÷\frac 89÷\frac 89$
$ =1×\frac 98×\frac 98$
$ =\frac {81}{64}$
$ =[\frac 7{11}+\frac 4{11}-\frac 8{15}]×\frac {45}{14}$
$ =[1-\frac 8{15}]×\frac {45}{14}$
$ =\frac 7{15}×\frac {45}{14}$
$ =\frac 32$
$ =3×\frac 7{12}$
$ =\frac 74$
$ =(21+\frac 7{12})×\frac 37$
$ =21×\frac 37+\frac 7{12}×\frac 37$
$ =9+\frac 14$
$ =9\frac 14$
$ =\frac {32}{33}×(33+1)$
$ =\frac {32}{33}×33+\frac {32}{33}$
$ =32+\frac {32}{33}$
$ =32\frac {32}{33}$
$ =[1-\frac 7{20}]×\frac {25}{26}$
$ =\frac {13}{20}×\frac {25}{26}$
$ =\frac 58$
$ =\frac 23+\frac 29+\frac 79$
$ =\frac 23+(\frac 29+\frac 79)$
$ =1\frac 23$
$ =(\frac 16-\frac 17)×42$
$ =\frac 16×42-\frac 17×42$
=7-6
=1
$ =\frac 27÷\frac 27÷\frac 89÷\frac 89$
$ =1×\frac 98×\frac 98$
$ =\frac {81}{64}$
$ =[\frac 7{11}+\frac 4{11}-\frac 8{15}]×\frac {45}{14}$
$ =[1-\frac 8{15}]×\frac {45}{14}$
$ =\frac 7{15}×\frac {45}{14}$
$ =\frac 32$