一、口算。
$31.2 - 30.08 =$
$0.56 ÷ 0.8 =$
$7.2 + 1.88 =$
$0.15 × 40 =$
$628 ÷ 2 =$
$3.14 × 0.5 =$
$1.44 ÷ 0.2 =$
$20 - 10.45 =$
$0.08 × 9.5 =$
$7.4 + 2.6 =$
$1.25 × 0.8 =$
$5.1 ÷ 17 =$
$\frac{5}{6} × 1.2 =$
$\frac{5}{9} ÷ \frac{5}{6} =$
$\frac{8}{9} ÷ \frac{8}{9} =$
$\frac{1}{100} ÷ \frac{1}{10} =$
$\frac{5}{4} × 4.8 =$
$\frac{1}{6} × \frac{9}{5} =$
$\frac{4}{7} + \frac{3}{4} =$
$\frac{14}{15} ÷ \frac{7}{3} =$
$\frac{4}{5} + \frac{1}{3} =$
$\frac{8}{9} × \frac{2}{3} =$
$2 - \frac{1}{5} =$
$81 ÷ \frac{9}{5} =$

1. 1.12
2. 0.7
3. 9.08
4. 6
5. 314
6. 1.57
7. 7.2
8. 9.55
9. 0.76
10. 10
11. 1
12. 0.3
13. 1
14. $\frac{2}{3}$
15. 1
16. $\frac{1}{10}$
17. 6
18. $\frac{3}{10}$
19. $\frac{37}{28}$
20. $\frac{2}{5}$
21. $\frac{17}{15}$
22. $\frac{16}{27}$
23. $\frac{9}{5}$
24. 45

二、计算下面各题，能简算的要简算。
$(\frac{4}{5} + \frac{1}{4}) ÷ \frac{7}{3} + \frac{7}{10}$
$\frac{8}{49} ÷ [\frac{9}{8} - (\frac{1}{8} + \frac{3}{7})]$
$960 × (1 - \frac{1}{4} - \frac{1}{6})$
$6.9 × 2.7 + 6.9 × 7.3$
$(71.2 - 71.2 × 0.9) ÷ 0.5$
$17.64 ÷ 4.9 + 5.73 + 1.37$

1. $\frac{23}{20}$
2. $\frac{2}{7}$
3. 560
4. 69
5. 14.24
6. 10.7