以下是1到20的立方根：

1. √1 = 1

2. √2 = 1.4142135623730951

3. √3 = 1.7320508075688772

4. √4 = 2

5. √5 = 2.23606797749979

6. √6 = 2.449489742783178

7. √7 = 2.6457513110645907

8. √8 = 2.8284271247461903

9. √9 = 3

10. √10 = 3.1622776601683795

11. √11 = 3.3166247903554

12. √12 = 3.4641016151377544

13. √13 = 3.6055512754639893

14. √14 = 3.7416573867739413

15. √15 = 3.872983346207416

16. √16 = 4

17. √17 = 4.1231056256176604

18. √18 = 4.242640687119285

19. √19 = 4.358898943540674

20. √20 = 4.472135954999579

这些是1到20的整数的立方根，其中1, 4, 9, 16是整数的立方根，其余的都是近似值，因为立方根通常不是整数。