一、口算。
$5.6×8=$
$0.96×5=$
$0.25×30=$
$0.2×808=$
$1.1×90=$
$4.6×5=$
$8.5×4=$
$0.08×8=$
$1.52×2=$
$0.19×3=$
$2.5×400=$
$0.81×60=$
$1.2×500=$
$0.01×120=$
$2.3×4=$
$\frac{9}{10}×\frac{2}{3}=$
$\frac{3}{8}×\frac{8}{5}=$
$\frac{1}{8}×\frac{6}{7}=$
$\frac{2}{5}×\frac{1}{4}=$
$\frac{5}{22}×2=$
$\frac{3}{4}×\frac{8}{27}=$
$\frac{6}{7}×\frac{3}{2}=$
$\frac{11}{18}×\frac{9}{5}=$
$\frac{9}{8}×\frac{3}{4}=$

1.$5.6×8=44.8$
2.$0.96×5=4.8$
3.$0.25×30=7.5$
4.$0.2×808=161.6$
5.$1.1×90=99$
6.$4.6×5=23$
7.$8.5×4=34$
8.$0.08×8=0.64$
9.$1.52×2=3.04$
10.$0.19×3=0.57$
11.$2.5×400=1000$
12.$0.81×60=48.6$
13.$1.2×500=600$
14.$0.01×120=1.2$
15.$2.3×4=9.2$
16.$\frac{9}{10}×\frac{2}{3}=\frac{3}{5}$
17.$\frac{3}{8}×\frac{8}{5}=\frac{3}{5}$
18.$\frac{1}{8}×\frac{6}{7}=\frac{3}{28}$
19.$\frac{2}{5}×\frac{1}{4}=\frac{1}{10}$
20.$\frac{5}{22}×2=\frac{5}{11}$
21.$\frac{3}{4}×\frac{8}{27}=\frac{2}{9}$
22.$\frac{6}{7}×\frac{3}{2}=\frac{9}{7}$
23.$\frac{11}{18}×\frac{9}{5}=\frac{11}{10}$
24.$\frac{9}{8}×\frac{3}{4}=\frac{27}{32}$

二、先想想积是几位小数，再计算。
$0.06×0.8=\frac{6}{( )}×\frac{8}{( )}=\frac{48}{( )}=( )$
$0.5×1.7=\frac{( )}{10}×\frac{( )}{10}=\frac{( )}{100}=( )$
$7×0.04=7×\frac{( )}{( )}=\frac{7×( )}{( )}=\frac{( )}{( )}=( )$
$3.9×0.02=\frac{( )}{( )}×\frac{( )}{( )}=\frac{( )}{( )}=( )$
$0.24×0.09=\frac{( )}{( )}×\frac{( )}{( )}=\frac{( )}{( )}=( )$

1.$0.06×0.8=\frac{6}{100}×\frac{8}{10}=\frac{48}{1000}=0.048$
2.$0.5×1.7=\frac{5}{10}×\frac{17}{10}=\frac{85}{100}=0.85$
3.$7×0.04=7×\frac{4}{100}=\frac{7×4}{100}=\frac{28}{100}=0.28$
4.$3.9×0.02=\frac{39}{10}×\frac{2}{100}=\frac{78}{1000}=0.078$
5.$0.24×0.09=\frac{24}{100}×\frac{9}{100}=\frac{216}{10000}=0.0216$