Teacher Trinh Quang Cao Son

1. Range converter
   
2. Pyramid codes
   
3. Rainbow
   
4. pond
   
5. Range converter 2
   
6. Phone number prefix
   
7. Nice number
   
8. Largest number of matches
   
9. Maximum value that splits two numbers
   
10. Scheduled
    
11. Find the number on the zig zag matrix
    
12. Maximum length of the range
    
13. Three factors
    
14. Perfect number(hard version)
    
15. Game addiction
    
16. Plentiful numbers(hard version)
    
17. Year value
    
18. Prime ( hard version )
    
19. Sàng nguyên tố
    
20. General estimate (hard version)
    
21. Số nguyên tố nhỏ hơn n