一、口算。
$\frac{2}{3}÷\frac{8}{9}=$
$2.4 + 0.56 =$
$300÷15 =$
$177×\frac{1}{3}=$
$72÷0.8 =$
$\frac{2}{7}×\frac{3}{20}=$
$\frac{4}{5}×\frac{3}{4}=$
$3-\frac{3}{2}=$
$\frac{5}{12}÷\frac{9}{10}=$
$3.75×4 =$
$1.9 - 0.09 =$
$85÷20 =$
$\frac{2}{5}+\frac{7}{10}=$
$\frac{1}{4}÷\frac{1}{64}=$
$\frac{3}{5}×\frac{10}{39}=$
$130÷6.5 =$
$\frac{13}{14}+\frac{3}{7}=$
$190 - 98 =$
$\frac{5}{12}-\frac{1}{4}=$
$7.5×4\% =$
$0.34÷\frac{1}{2}=$

一、$\dfrac{3}{4}$ 2.96 20
59 90 $\dfrac{3}{70}$
$\dfrac{3}{5}$ $\dfrac{3}{2}$ $\dfrac{25}{54}$
15 1.81 4.25
$\dfrac{11}{10}$ 16 $\dfrac{2}{13}$
20 $\dfrac{19}{14}$ 92

二、解比例。
$1.4:2 = x:40$
$\frac{1}{10}:x=\frac{1}{8}:\frac{1}{4}$
$x:18 = 5:4$
$\frac{3.3}{4.4}=\frac{9}{x}$
$x:\frac{17}{18}=\frac{18}{19}:17$
$15:\frac{2}{3}=6:x$

二、$x=28$ $x=\dfrac{1}{5}$ $x=22.5$
$x=12$ $x=\dfrac{1}{19}$ $x=\dfrac{4}{15}$