一、口算。
$630÷70=$
$304×3=$
$126÷6=$
$7.6×100=$
$9.6÷60=$
$2.15×0.4=$
$5×2.2=$
$1.8÷0.18=$
$109×6=$
$10÷0.5=$
$0.5×0.8=$
$63×6=$
$120×2=$
$900÷6=$
$750÷2=$
$\frac{5}{8}×\frac{2}{5}=$
$\frac{9}{10}÷\frac{3}{25}=$
$\frac{14}{3}×\frac{2}{7}=$
$\frac{10}{21}÷\frac{2}{7}=$
$\frac{3}{4}×\frac{16}{9}=$
$\frac{3}{4}÷\frac{9}{10}=$
$\frac{2}{17}÷\frac{8}{17}=$
$\frac{6}{7}×\frac{3}{4}=$
$\frac{3}{8}×\frac{2}{9}=$

1. $630÷70=9$
2. $304×3=912$
3. $126÷6=21$
4. $7.6×100=760$
5. $9.6÷60=0.16$
6. $2.15×0.4=0.86$
7. $5×2.2=11$
8. $1.8÷0.18=10$
9. $109×6=654$
10. $10÷0.5=20$
11. $0.5×0.8=0.4$
12. $63×6=378$
13. $120×2=240$
14. $900÷6=150$
15. $750÷2=375$
16. $\frac{5}{8}×\frac{2}{5}=\frac{1}{4}$
17. $\frac{9}{10}÷\frac{3}{25}=\frac{15}{2}$
18. $\frac{14}{3}×\frac{2}{7}=\frac{4}{3}$
19. $\frac{10}{21}÷\frac{2}{7}=\frac{5}{3}$
20. $\frac{3}{4}×\frac{16}{9}=\frac{4}{3}$
21. $\frac{3}{4}÷\frac{9}{10}=\frac{5}{6}$
22. $\frac{2}{17}÷\frac{8}{17}=\frac{1}{4}$
23. $\frac{6}{7}×\frac{3}{4}=\frac{9}{14}$
24. $\frac{3}{8}×\frac{2}{9}=\frac{1}{12}$

二、先想一想每个数的计数单位，再填空。
0.05×1.7
=(0.01×□)×(0.1×□)
=(0.01×0.1)×(□×□)
=□×□
0.21÷0.3
=(0.01×□)÷(0.1×□)
=(0.01÷0.1)×(□÷□)
=□×□
$\frac{3}{8}×5$
=$(\frac{1}{8}×□)×(1×□)$
=$(\frac{1}{8}×1)×(□×□)$
=□×□
$\frac{4}{5}÷\frac{2}{7}$
=$(□×4)÷(□×2)$
=$(□÷□)×(4÷2)$
=□×□

1. 0.05×1.7
=(0.01×5)×(0.1×17)
=(0.01×0.1)×(5×17)
=0.001×85
2. 0.21÷0.3
=(0.01×21)÷(0.1×3)
=(0.01÷0.1)×(21÷3)
=0.1×7
3. $\frac{3}{8}×5$
=$(\frac{1}{8}×3)×(1×5)$
=$(\frac{1}{8}×1)×(3×5)$
=$\frac{1}{8}×15$
4. $\frac{4}{5}÷\frac{2}{7}$
=$(\frac{1}{5}×4)÷(\frac{1}{7}×2)$
=$(\frac{1}{5}÷\frac{1}{7})×(4÷2)$
=$\frac{7}{5}×2$