一、口算。
$71 - 17 =$
$17 × 5 =$
$0.4 + 2 =$
$51 ÷ 3 =$
$25 + 68 =$
$74 ÷ 37 =$
$200 - 137 =$
$720 ÷ 8 =$
$6 × 106 =$
$0.423 × 10 =$
$3.8 + 1.26 =$
$0.89 - 0.5 =$
$790 ÷ 100 =$
$0.04 × 6 =$
$23.2 ÷ 8 =$
$0.82 - 0.28 =$
$3.44 ÷ 4 =$
$2.06 × 4 =$
$41 × 300 =$
$1.75 + 1.75 =$
$900 ÷ 15 =$
$10 - 2.87 =$
$0.24 × 50 =$
$7.2 ÷ 36 =$

1. 54
2. 85
3. 2.4
4. 17
5. 93
6. 2
7. 63
8. 90
9. 636
10. 4.23
11. 5.06
12. 0.39
13. 7.9
14. 0.24
15. 2.9
16. 0.54
17. 0.86
18. 8.24
19. 12300
20. 3.5
21. 60
22. 7.13
23. 12
24. 0.2

二、用竖式计算。
$27÷45=$
$3.7×24=$
$79.5÷15=$
$1.44×50=$
$3.51÷78=$
$3.06×59=$

1. 0.6
2. 88.8
3. 5.3
4. 72
5. 0.045
6. 180.54