一、口算。
$24.6÷ 3=$
$36.8-12.4=$
$20.8÷ 4=$
$28.28÷ 14=$
$24× 40=$
$314÷ 100=$
$2.54+1.89=$
$8.77× 0.1=$
$6.5× 0.08=$
$155-5.5=$
$388+137=$
$5.6+3.6=$
$10÷ \dfrac{4}{9}=$
$\dfrac{3}{2}+\dfrac{3}{4}=$
$\dfrac{2}{3}÷ \dfrac{1}{2}=$
$4.5× \dfrac{7}{9}=$
$\dfrac{12}{7}× \dfrac{1}{2}=$
$\dfrac{2}{7}-\dfrac{1}{8}=$
$\dfrac{5}{9}÷ \dfrac{20}{3}=$
$\dfrac{8}{25}÷ 0.8=$
$\dfrac{2}{5}-\dfrac{2}{7}=$
$\dfrac{11}{12}-\dfrac{5}{8}=$
$\dfrac{12}{5}× \dfrac{1}{6}=$
$\dfrac{1}{8}÷ \dfrac{1}{4}=$

1.$8.2$
2.$24.4$
3.$5.2$
4.$2.02$
5.$960$
6.$3.14$
7.$4.43$
8.$0.877$
9.$0.52$
10.$149.5$
11.$525$
12.$9.2$
13.$\dfrac{45}{2}$
14.$\dfrac{9}{4}$
15.$\dfrac{4}{3}$
16.$\dfrac{7}{2}$
17.$\dfrac{6}{7}$
18.$\dfrac{9}{56}$
19.$\dfrac{1}{12}$
20.$\dfrac{2}{5}$
21.$\dfrac{4}{35}$
22.$\dfrac{7}{24}$
23.$\dfrac{2}{5}$
24.$\dfrac{1}{2}$

二、根据比例的基本性质，在括号里填合适的数。
$4:3.25=(\quad):\frac{1}{2}$
$\frac{5}{2}:(\quad)=\frac{8}{7}:\frac{2}{5}$
$3.6:(\quad)=0.8:1.2$
$(\quad):0.5=\frac{2}{3}:4$
$0.6:(\quad)=\frac{2}{7}:\frac{3}{4}$
$\frac{5}{8}:0.3=\frac{1}{6}:(\quad)$
$0.5:1.2=2.5:(\quad)$
$\frac{2}{5}:(\quad)=\frac{1}{5}:0.6$
$1.6:(\quad)=2.5:5$
$(\quad):\frac{1}{4}=13.6:2$
$\frac{1}{3}:\frac{1}{20}=\frac{16}{9}:(\quad)$
$(\quad):\frac{3}{4}=3.6:\frac{8}{3}$
$\frac{2}{3}:\frac{2}{9}=21:(\quad)$
$0.2:\frac{3}{4}=\frac{4}{5}:(\quad)$
$\frac{4}{3}:(\quad)=0.75:1.8$

1.$\dfrac{8}{13}$
2.$\dfrac{7}{8}$
3.$5.4$
4.$\dfrac{1}{12}$
5.$\dfrac{63}{40}$
6.$\dfrac{2}{25}$
7.$6$
8.$1.2$
9.$3.2$
10.$1.7$
11.$\dfrac{4}{15}$
12.$\dfrac{81}{80}$
13.$7$
14.$3$
15.$3.2$