一、口算。
$3.9×0.7=$ $77÷0.7=$ $1.02-0.09=$
$305+789=$ $3.68+1.34=$ $328÷8=$
$0.94-0.65=$ $0.8×0.16=$ $3.9+6.1=$
$48×50=$ $500-234=$ $40.8÷0.8=$
$\frac{5}{8}÷\frac{5}{7}=$ $\frac{2}{3}+\frac{1}{8}=$ $\frac{7}{8}×\frac{8}{7}=$
$\frac{2}{3}÷\frac{3}{4}=$ $\frac{5}{12}×\frac{4}{15}=$ $\frac{4}{5}-\frac{7}{10}=$
$\frac{3}{2}×\frac{16}{15}=$ $\frac{3}{4}-\frac{1}{3}=$ $9×\frac{5}{9}=$
$\frac{5}{8}÷1.5=$ $\frac{1}{16}÷\frac{1}{12}=$ $15÷\frac{3}{5}=$

1.$3.9×0.7=2.73$
2.$77÷0.7=110$
3.$1.02-0.09=0.93$
4.$305+789=1094$
5.$3.68+1.34=5.02$
6.$328÷8=41$
7.$0.94-0.65=0.29$
8.$0.8×0.16=0.128$
9.$3.9+6.1=10$
10.$48×50=2400$
11.$500-234=266$
12.$40.8÷0.8=51$
13.$\frac{5}{8}÷\frac{5}{7}=\frac{7}{8}$
14.$\frac{2}{3}+\frac{1}{8}=\frac{19}{24}$
15.$\frac{7}{8}×\frac{8}{7}=1$
16.$\frac{2}{3}÷\frac{3}{4}=\frac{8}{9}$
17.$\frac{5}{12}×\frac{4}{15}=\frac{1}{9}$
18.$\frac{4}{5}-\frac{7}{10}=\frac{1}{10}$
19.$\frac{3}{2}×\frac{16}{15}=\frac{8}{5}$
20.$\frac{3}{4}-\frac{1}{3}=\frac{5}{12}$
21.$9×\frac{5}{9}=5$
22.$\frac{5}{8}÷1.5=\frac{5}{12}$
23.$\frac{1}{16}÷\frac{1}{12}=\frac{3}{4}$
24.$15÷\frac{3}{5}=25$

二、根据比例的基本性质，在括号里填合适的数。
$\frac{5}{12}:( )=2:9$
$\frac{1}{3}:( )=\frac{7}{5}:\frac{9}{5}$
$( ):3=0.6:4$
$( ):1.2=3:4$
$2.5:0.9=30:( )$
$\frac{5}{2}:( )=\frac{1}{20}:\frac{1}{5}$
$1.2:5=24:( )$
$( ):\frac{3}{4}=16:36$
$2.5:3=10:( )$
$\frac{3}{2}:\frac{1}{5}=\frac{3}{4}:( )$
$( ):8=\frac{3}{4}:\frac{1}{5}$
$( ):12=0.16:16$
$\frac{1}{3}:\frac{2}{5}=( ):\frac{3}{4}$
$0.6:( )=\frac{1}{24}:\frac{1}{8}$
$4.5:\frac{3}{4}=( ):\frac{4}{3}$

1.$\frac{15}{8}$
2.$\frac{3}{7}$
3.$0.45$
4.$0.9$
5.$10.8$
6.$10$
7.$100$
8.$\frac{1}{3}$
9.$12$
10.$\frac{1}{10}$
11.$30$
12.$0.12$
13.$\frac{5}{8}$
14.$1.8$
15.$8$