一、口算。
$5.2 - 1.78 =$
$125 × 0.08 =$
$4.2 ÷ 0.07 =$
$3.14 × 0 =$
$35 ÷ 0.05 =$
$7.89 - 3.9 =$
$0.57 + 2.3 =$
$0.72 + 4.2 =$
$4.5 × 0.08 =$
$6.6 - 0.66 =$
$11.7 ÷ 0.3 =$
$8.8 ÷ 1.1 =$
$\frac{1}{8} ×5 =$
$\frac{5}{6} + \frac{3}{8} =$
$40 × \frac{2}{5} =$
$\frac{1}{15} + \frac{1}{5} =$
$\frac{5}{7} × \frac{2}{5} =$
$\frac{2}{3} × \frac{2}{7} =$
$\frac{4}{9} ÷ \frac{4}{3} =$
$\frac{6}{7} ÷ \frac{3}{14} =$
$\frac{1}{2} ÷ \frac{1}{4} =$
$\frac{2}{3} ÷ \frac{4}{9} =$
$\frac{8}{25} ÷ \frac{4}{5} =$
$12 ÷ \frac{3}{8} =$

1. 3.42
2. 10
3. 60
4. 0
5. 700
6. 3.99
7. 2.87
8. 4.92
9. 0.36
10. 5.94
11. 39
12. 8
13. $\frac{5}{8}$
14. $\frac{29}{24}$
15. 16
16. $\frac{4}{15}$
17. $\frac{2}{7}$
18. $\frac{4}{21}$
19. $\frac{1}{3}$
20. 4
21. 2
22. $\frac{3}{2}$
23. $\frac{2}{5}$
24. 32

二、计算下面各题，能简算的要简算。
$\frac{7}{13} × \frac{4}{5} + \frac{6}{13} ÷ \frac{5}{4}$
$(2.5 + \frac{5}{8} + \frac{5}{12}) ÷ 5$
$\frac{8}{7} - (\frac{1}{9} - \frac{1}{12}) × 3.6$
$7.08 × 101 - 7.08$
$79.8 ÷ 4.2 + 79.8 ÷ 3.8$
$52 ÷ [1.6 × (4.1 - 0.85)]$

1. $\frac{4}{5}$
2. $\frac{17}{24}$
3. $\frac{73}{70}$
4. 708
5. 40
6. 10