1. Linear programming
2. mathematical induction
3. arch
4. amount of cube power
5. basic concept
6. 30 degrees
7. solution set
8. programming language
9. contradiction method
10. Number theory
11 Mathematical logic
12. Theorem
13. Intersect
14. Elimination
15. Gauss Method
16. Plane diagonal
17. Side diagonal
18. ... diagonal
19. Factorial
20. Permutation