一、口算。
$5 - 3.39 =$
$9.09 + 0.91 =$
$1676 + 524 =$
$2.13 × 0.1 =$
$5.8 × 0.4 =$
$8.4 ÷ 0.04 =$
$1 ÷ 0.25 =$
$0.75 × 0.2 =$
$3.12 - 2.13 =$
$65 ÷ 5 =$
$73 - 19 =$
$54 × 30 =$
$\frac{7}{27} × \frac{9}{14} =$
$7 ÷ \frac{3}{5} =$
$3 - \frac{11}{9} =$
$\frac{3}{4} - \frac{5}{18} =$
$\frac{7}{9} ÷ \frac{7}{6} =$
$\frac{7}{12} + \frac{5}{9} =$
$34 ÷ \frac{17}{2} =$
$0.75 ÷ \frac{3}{8} =$
$\frac{5}{6} + 0.5 =$
$\frac{5}{7} × \frac{14}{45} =$
$\frac{5}{14} - \frac{2}{7} =$
$10 × \frac{2}{5} =$

1. 1.61
2. 10
3. 2200
4. 0.213
5. 2.32
6. 210
7. 4
8. 0.15
9. 0.99
10. 13
11. 54
12. 1620
13. $\frac{1}{6}$
14. $\frac{35}{3}$
15. $\frac{16}{9}$
16. $\frac{17}{36}$
17. $\frac{2}{3}$
18. $\frac{41}{36}$
19. 4
20. 2
21. $\frac{4}{3}$
22. $\frac{2}{9}$
23. $\frac{1}{14}$
24. 4

二、根据比例的基本性质，在括号里填合适的数。
$8:3.2=1.25:( )$
$9:8=13.5:( )$
$( ):4=\frac{4}{5}:8$
$\frac{1}{6}:\frac{1}{20}=\frac{16}{9}:( )$
$\frac{4}{3}:\frac{8}{25}=( ):\frac{4}{25}$
$2.7:( )=5:\frac{5}{4}$
$( ):30=15:18$
$\frac{18}{5}:\frac{3}{5}=( ):\frac{1}{3}$
$0.24:0.4=( ):5$
$( ):84=\frac{5}{7}:10$
$( ):\frac{1}{2}=12:\frac{3}{5}$
$3:4=\frac{1}{20}:( )$
$0.7:\frac{2}{7}=( ):20$
$10:( )=\frac{2}{3}:\frac{4}{5}$
$( ):2.4=15:0.8$

1. 0.5
2. 12
3. $\frac{2}{5}$
4. $\frac{8}{15}$
5. $\frac{2}{3}$
6. $\frac{27}{40}$
7. 25
8. 2
9. 3
10. 6
11. 49
12. 12
13. $\frac{1}{15}$
14. 49
15. 12
16. 45