一、口算。
$1.6÷0.32=$ $0.9+9.09=$ $7-0.77=$
$0.45×0.8=$ $1.4×0.07=$ $\dfrac{11}{12}+\dfrac{1}{6}=$
$\dfrac{2}{5}+\dfrac{1}{4}=$ $5-\dfrac{4}{3}=$ $2.4÷0.75=$
$\dfrac{7}{9}×\dfrac{45}{46}=$ $50\%÷\dfrac{6}{7}=$ $7.85+2.25=$
$9.2-1.52=$ $300×10\%=$ $20.8\%-8\%=$
$\dfrac{3}{4}÷\dfrac{7}{10}=$ $5\%÷5=$ $1.08+12\%=$
$\dfrac{9}{7}+\dfrac{12}{7}=$ $\dfrac{2}{5}-\dfrac{1}{20}=$ $200×\dfrac{1}{4}=$

一、5 9.99 6.23 0.36 0.098 $\dfrac{13}{12}$ $\dfrac{13}{20}$ $\dfrac{11}{3}$ 3.2 $\dfrac{35}{46}$ $\dfrac{7}{12}$ 10.1 7.68 30 12.8% $\dfrac{15}{14}$ 0.01 1.2 3 $\dfrac{7}{20}$ 50

二、解比例。
$\dfrac{3.2}{x}=\dfrac{2}{5}$ $x:0.75=\dfrac{5}{6}:0.5$ $\dfrac{1}{2}:x=\dfrac{3}{4}:6$
$\dfrac{1}{4}:x=\dfrac{1}{6}:24$ $\dfrac{1}{8}:\dfrac{3}{16}=8:x$ $\dfrac{3}{4}:\dfrac{5}{12}=(x-\dfrac{1}{2}):\dfrac{2}{3}$

二、$x=8$ $x=\dfrac{5}{4}$ $x=4$ $x=36$ $x=12$ $x=\dfrac{17}{10}$

解：$\dfrac{3.2}{x}=\dfrac{2}{5}$
2x=3 sixe.
（1)