一、口算。
0.31×500＝
0.25×0.4＝
28×0.3＝
0.83×0.5＝
0.4×0.5＝
3.15×3＝
5.2×2＝
0.2×0.04＝
7.6×0.01＝
1.6×0.3＝
0.5×100＝
9×3.7＝
0.17×0.2＝
2.7×0.3＝
0.3×0.9＝
3×2.3＝
0.07×0.8＝
0.36×20＝
6×0.25＝
5×2.4＝
6×0.15＝
0.11×0.8＝
2.1×0.7＝
0.72×30＝

1. 0.31×500=155
2. 0.25×0.4=0.1
3. 28×0.3=8.4
4. 0.83×0.5=0.415
5. 0.4×0.5=0.2
6. 3.15×3=9.45
7. 5.2×2=10.4
8. 0.2×0.04=0.008
9. 7.6×0.01=0.076
10. 1.6×0.3=0.48
11. 0.5×100=50
12. 9×3.7=33.3
13. 0.17×0.2=0.034
14. 2.7×0.3=0.81
15. 0.3×0.9=0.27
16. 3×2.3=6.9
17. 0.07×0.8=0.056
18. 0.36×20=7.2
19. 6×0.25=1.5
20. 5×2.4=12
21. 6×0.15=0.9
22. 0.11×0.8=0.088
23. 2.1×0.7=1.47
24. 0.72×30=21.6

二、用竖式计算。
$4.35×1.9=$ $4.08×3.2=$ $0.65×3.4=$

$0.16×0.42=$ $0.028×1.2=$ $3.59×0.16=$

1. 4.35×1.9=8.265
2. 4.08×3.2=13.056
3. 0.65×3.4=2.21
4. 0.16×0.42=0.0672
5. 0.028×1.2=0.0336
6. 3.59×0.16=0.5744