一、口算。
$7.5×20=$
$720÷40=$
$0.38×200=$
$2.7÷0.27=$
$4-1.99=$
$710+595=$
$6.66÷20=$
$7.34×5=$
$9.06÷0.3=$
$600×0.09=$
$77.2-32.1=$
$901-377=$
$12÷\frac{3}{4}=$
$\frac{2}{15}+0.15=$
$\frac{5}{8}÷\frac{5}{12}=$
$\frac{3}{4}+\frac{1}{5}=$
$\frac{1}{2}×\frac{1}{10}=$
$\frac{11}{4}×\frac{2}{11}=$
$\frac{5}{2}÷\frac{1}{4}=$
$0.75÷\frac{2}{5}=$
$12×\frac{5}{6}=$
$\frac{3}{4}+\frac{3}{20}=$
$\frac{2}{3}÷\frac{3}{20}=$
$\frac{5}{8}-\frac{3}{5}=$

1. 150
2. 18
3. 76
4. 10
5. 2.01
6. 1305
7. 0.333
8. 36.7
9. 30.2
10. 54
11. 45.1
12. 524
13. 16
14. $\frac{17}{60}$
15. $\frac{3}{2}$
16. $\frac{19}{20}$
17. $\frac{1}{20}$
18. $\frac{1}{2}$
19. 10
20. $\frac{15}{8}$
21. 10
22. $\frac{9}{10}$
23. $\frac{40}{9}$
24. $\frac{1}{40}$

二、根据比例的基本性质，在括号里填合适的数。
$35:(\ )=\frac{7}{8}:6$
$\frac{8}{9}:(\ )=\frac{1}{2}:\frac{3}{4}$
$\frac{1}{15}:\frac{1}{3}=\frac{4}{5}:(\ )$
$\frac{5}{9}:(\ )=\frac{1}{3}:\frac{6}{5}$
$\frac{5}{7}:(\ )=\frac{5}{8}:\frac{7}{9}$
$\frac{3}{4}:(\ )=\frac{6}{5}:\frac{9}{4}$
$\frac{1}{6}:\frac{5}{9}=(\ ):\frac{2}{3}$
$0.85:(\ )=\frac{1}{2}:2$
$\frac{8}{21}:16=\frac{2}{7}:(\ )$
$(\ ):6=22.5:9$
$\frac{5}{8}:\frac{3}{4}=(\ ):\frac{6}{7}$
$6:15=(\ ):\frac{2}{3}$
$(\ ):4=\frac{1}{6}:7$
$2.8:\frac{7}{8}=56:(\ )$
$0.6:(\ )=0.2:7.5$

1. 240
2. $\frac{4}{3}$
3. 4
4. 2
5. $\frac{8}{9}$
6. $\frac{45}{32}$
7. $\frac{1}{5}$
8. 3.4
9. 12
10. 15
11. $\frac{5}{7}$
12. $\frac{4}{15}$
13. $\frac{2}{21}$
14. 17.5
15. 22.5