1. 直接写出得数。
$ \frac{5}{12} + \frac{1}{5} = $$ $$ \frac{5}{3} - \frac{8}{21} = $$ $$ \frac{8}{5} - \frac{1}{2} = $$ $$ \frac{5}{7} + \frac{1}{5} + \frac{3}{10} = $
$ \frac{5}{9} × \frac{1}{5} = $$ $$ 36 × \frac{1}{54} = $$ $$ 20 × \frac{4}{25} = $$ $$ \frac{13}{56} × \frac{4}{13} × 3 = $
$ \frac{1}{4} × \frac{2}{5} = $$ $$ \frac{18}{25} × \frac{15}{16} = $$ $$ \frac{26}{63} × \frac{28}{39} = $$ $$ \frac{25}{41} × \frac{41}{25} × \frac{21}{25} = $
$ \frac{1}{6} × \frac{5}{6} = $$ $$ \frac{17}{19} × \frac{38}{51} = $$ $$ \frac{11}{15} × \frac{25}{33} = $$ $$ \frac{7}{18} × \frac{9}{49} × \frac{7}{2} = $
$ \frac{12}{13} × \frac{3}{2} = $$ $$ \frac{11}{12} × \frac{3}{22} = $$ $$ \frac{30}{7} × \frac{35}{24} = $$ $$ \frac{13}{17} × \frac{34}{13} × \frac{1}{2} = $
$ \frac{9}{28} × \frac{7}{36} = $$ $$ \frac{3}{4} × \frac{6}{5} = $$ $$ \frac{5}{14} × 35 = $$ $$ \frac{11}{13} × \frac{26}{55} × \frac{5}{13} = $

1. $\dfrac{37}{60}$ $\dfrac{9}{7}$ $\dfrac{11}{10}$ $\dfrac{17}{14}$
$\dfrac{1}{9}$ $\dfrac{2}{3}$ $\dfrac{16}{5}$ $\dfrac{3}{14}$
$\dfrac{1}{10}$ $\dfrac{27}{40}$ $\dfrac{8}{27}$ $\dfrac{21}{25}$
$\dfrac{5}{36}$ $\dfrac{2}{3}$ $\dfrac{5}{9}$ $\dfrac{1}{4}$
$\dfrac{18}{13}$ $\dfrac{1}{8}$ $\dfrac{25}{4}$ $1$
$\dfrac{1}{16}$ $\dfrac{9}{10}$ $\dfrac{25}{2}$ $\dfrac{2}{13}$

2. 计算下面各题。
$ \frac{4}{7} × \frac{5}{8} × \frac{21}{25} $$ $$ \frac{10}{11} × 132 × \frac{3}{5} $$ $$ \frac{10}{9} × \frac{7}{15} × \frac{12}{35} $
$ \frac{11}{7} × \frac{2}{3} × \frac{21}{22} $$ $$ \frac{7}{18} × \frac{3}{7} × 9 $$ $$ \frac{21}{10} × \frac{2}{5} × \frac{4}{7} $

2. $\dfrac{3}{10}$ $72$ $\dfrac{8}{45}$
$1$ $\dfrac{3}{2}$ $\dfrac{12}{25}$

填一填：$ \frac{1 × 3 × 11 + 2 × 6 × 22 + 3 × 9 × 33}{1 × 2 × 17 + 2 × 4 × 34 + 3 × 6 × 51} = ($　　$)。$　　

思维提升
$\dfrac{33}{34}$