一、口算。
0.26 + 0.4 =
0.4 × 0.75 =
4.6 + 4 =
0.64 ÷ 8 =
0.081 × 20 =
0.9 × 0.3 =
0.9 - 0.42 =
2.07 × 0.3 =
0.19 - 0.13 =
0.5 ÷ 4 =
0.16 ÷ 0.4 =
7.2 ÷ 9 =
$4 ÷ \frac{8}{15} =$
$\frac{9}{16} + \frac{15}{8} =$
$\frac{6}{13} × \frac{7}{4} =$
$\frac{5}{12} ÷ \frac{9}{20} =$
$\frac{3}{5} ÷ 6 =$
$\frac{15}{16} × \frac{4}{5} =$
$\frac{1}{2} + \frac{2}{5} =$
$\frac{1}{40} ÷ \frac{5}{8} =$
$\frac{4}{15} - \frac{1}{4} =$
$\frac{1}{2} × \frac{6}{5} =$
$\frac{3}{8} ÷ \frac{3}{4} =$
$\frac{3}{4} - \frac{3}{5} =$

1. 0.66
2. 0.3
3. 8.6
4. 0.08
5. 1.62
6. 0.27
7. 0.48
8. 0.621
9. 0.06
10. 0.125
11. 0.4
12. 0.8
13. $\frac{15}{2}$
14. $\frac{39}{16}$
15. $\frac{21}{26}$
16. $\frac{25}{27}$
17. $\frac{1}{10}$
18. $\frac{3}{4}$
19. $\frac{9}{10}$
20. $\frac{1}{25}$
21. $\frac{1}{60}$
22. $\frac{3}{5}$
23. $\frac{1}{2}$
24. $\frac{3}{20}$

二、计算下面各题，能简算的要简算。
$(\dfrac{2}{5} + \dfrac{3}{8}) ÷ (\dfrac{9}{10} - \dfrac{1}{2})$
$\dfrac{5}{18} × (\dfrac{11}{24} + \dfrac{1}{8}) ÷ \dfrac{5}{6}$
$[2 - (\dfrac{1}{4} + \dfrac{1}{8})] ÷ \dfrac{5}{4}$
$0.38 + 9.6 ÷ 3.2$
$8.6 × 0.6 + 8.6 × 0.4$
$3.75 ÷ [3 × (1.34 - 0.84)]$

1. $\frac{31}{16}$
2. $\frac{7}{36}$
3. $\frac{13}{10}$
4. 3.38
5. 8.6
6. 2.5