您好，以下是四年级下册数学小数加减法脱式计算的40道题目：
1. 0.4 + 0.3 =
2. 0.8 - 0.2 =
3. 1.5 + 0.7 =
4. 2.3 - 0.5 =
5. 0.6 + 0.4 =
6. 1.2 - 0.3 =
7. 2.5 + 0.9 =
8. 1.8 - 0.6 =
9. 0.9 + 0.2 =
10. 1.5 - 0.8 =
11. 0.3 + 0.7 =
12. 1.9 - 0.4 =
13. 3.2 + 0.1 =
14. 2.7 - 0.6 =
15. 0.5 + 0.6 =
16. 1.3 - 0.2 =
17. 2.8 + 0.4 =
18. 2.1 - 0.7 =
19. 0.2 + 0.5 =
20. 1.6 - 0.9 =
21. 0.6 + 0.9 =
22. 1.5 - 0.4 =
23. 2.7 + 0.3 =
24. 2.2 - 0.6 =
25. 0.7 + 0.3 =
26. 1.4 - 0.2 =
27. 2.6 + 0.8 =
28. 2.3 - 0.9 =
29. 0.9 + 0.1 =
30. 1.7 - 0.5 =
31. 0.5 + 0.8 =
32. 1.2 - 0.7 =
33. 2.5 + 0.2 =
34. 2.1 - 0.3 =
35. 0.3 + 0.4 =
36. 1.1 - 0.1 =
37. 2.4 + 0.6 =
38. 2.9 - 0.8 =
39. 0.8 + 0.1 =
40. 1.9 - 0.6 =
希望以上的题目能够帮助到你！
