一、口算。
$ \frac{29}{36} + \frac{3}{36} = $ $ \frac{5}{4} - \frac{3}{4} = $ $ \frac{6}{12} + \frac{5}{12} = $
$ \frac{19}{23} - \frac{4}{23} = $ $ \frac{7}{9} + \frac{7}{9} = $ $ \frac{27}{10} - \frac{3}{10} = $
$ \frac{3}{8} + \frac{17}{8} = $ $ \frac{17}{32} - \frac{9}{32} = $ $ \frac{4}{15} + \frac{9}{15} = $
$ 2.5×16 = $ $ 28.8÷4 = $ $ 3.2 - 1.34 - 1.66 = $
$ 2.8 - 0.28 = $ $ 8.4×5 = $ $ 0.8 + (1.2 - 0.8) = $
$ 3.8÷0.19 = $ $ 19.6÷0.7 = $ $ (1 - 0.45)÷0.5 = $
$ 4.06×0.5 = $ $ 0.75 + 12.5 = $ $ 0.7 + 0.3×3 = $
$ 3.06 + 1.94 = $ $ 1.25×0.04 = $ $ 0.04÷0.04 + 0.9 = $

一、$\frac{8}{9}$ $\frac{1}{2}$ $\frac{11}{12}$
$\frac{15}{23}$ $\frac{14}{9}$ $\frac{12}{5}$
$\frac{5}{2}$ $\frac{1}{4}$ $\frac{13}{15}$
40 7.2 0.2
2.52 42 1.2
20 28 1.1
2.03 13.25 1.6
5 0.05 1.9

二、先通分，再比较大小。
$ \frac{11}{12} $$和$$ \frac{9}{10} $$ $$ \frac{20}{39} $$和$$ \frac{7}{13} $$ $$ \frac{5}{9} $$和$$ \frac{7}{12} $
$ \frac{5}{22} $$和$$ \frac{7}{33} $$ $$ \frac{13}{23} $$和$$ \frac{29}{69} $$ $$ \frac{17}{9} $$和$$ \frac{23}{10} $

二、$\frac{11}{12}=\frac{55}{60}$ $\frac{9}{10}=\frac{54}{60}$ $\frac{11}{12}＞\frac{9}{10}$
$\frac{20}{39}=\frac{20}{39}$ $\frac{7}{13}=\frac{21}{39}$ $\frac{20}{39}＜\frac{7}{13}$
$\frac{5}{9}=\frac{20}{36}$ $\frac{7}{12}=\frac{21}{36}$ $\frac{5}{9}＜\frac{7}{12}$
$\frac{5}{22}=\frac{15}{66}$ $\frac{7}{33}=\frac{14}{66}$ $\frac{5}{22}＞\frac{7}{33}$
$\frac{13}{23}=\frac{39}{69}$ $\frac{29}{69}=\frac{29}{69}$ $\frac{13}{23}＞\frac{29}{69}$
$\frac{17}{9}=\frac{170}{90}$ $\frac{23}{10}=\frac{207}{90}$ $\frac{17}{9}＜\frac{23}{10}$