一、口算。
$1.53 + 2.7 =$
$6.24 ÷ 3 =$
$0.34 × 100 ÷ 0.1 =$
$0.9 × 600 =$
$8.92 - 8.2 =$
$1.6 ÷ 0.08 × 0.5 =$
$4.2 ÷ 30 =$
$75 × 40 =$
$7.3 + 12.7 - 0.5 =$
$0.21 ÷ 0.7 =$
$4.55 + 1.6 =$
$5.35 - (1.35 + 2.5) =$
$\frac{3}{4} ÷ \frac{4}{3} =$
$\frac{4}{5} + \frac{1}{8} =$
$14 ÷ ( \frac{4}{5} - \frac{9}{20} ) =$
$\frac{2}{3} + \frac{2}{5} =$
$\frac{7}{10} ÷ \frac{1}{2} =$
$( \frac{2}{87} - \frac{1}{58} ) ÷ \frac{1}{29} =$
$\frac{11}{6} ÷ \frac{22}{3} =$
$\frac{2}{3} + \frac{5}{12} =$
$\frac{4}{9} × \frac{1}{5} ÷ \frac{4}{5} =$
$\frac{1}{12} ÷ \frac{4}{15} =$
$\frac{1}{9} - \frac{1}{10} =$
$\frac{6}{7} × 2 ÷ \frac{6}{7} × 2 =$

1. 4.23
2. 2.08
3. 340
4. 540
5. 0.72
6. 10
7. 0.14
8. 3000
9. 19.5
10. 0.3
11. 6.15
12. 1.5
13. $\frac{9}{16}$
14. $\frac{37}{40}$
15. 40
16. $\frac{16}{15}$
17. $\frac{7}{5}$
18. $\frac{1}{6}$
19. $\frac{1}{4}$
20. $\frac{13}{12}$
21. $\frac{1}{9}$
22. $\frac{5}{16}$
23. $\frac{1}{90}$
24. 4

二、用竖式计算。
0.65×1.88=
6.11÷9.4=
9.09×7.6=
7.91÷2.26=
2.58×0.44≈
（得数保留两位小数）
21.2÷3.88≈
（得数保留两位小数）

1. 1.222
2. 0.65
3. 69.084
4. 3.5
5. 1.14
6. 5.46