Numero Uno/Dogfight

Here's a bunch of two-player games I found from 2004, each with a separate level of difficulty. The aim is to guess the other's number by using multiplication and division. 
Each is a separate game and should be treated that way.

1. One-Digit Numero Uno
2. Two-Digit Numero Uno
3. Three-Digit Numero Uno
4. Four-Digit Numero Uno
5. Five-Digit Numero Uno
6. Six-Digit Numero Uno
7. Seven-Digit Numero Uno
8. Eight-Digit Numero Uno
9. Nine-Digit Numero Uno
10. One-Digit Dogfight
11. Two-Digit Dogfight
12. Three-Digit Dogfight
13. Four-Digit Dogfight
14. Five-Digit Dogfight
15. Six-Digit Dogfight
16. Seven-Digit Dogfight
17. Eight-Digit Dogfight
18. Nine-Digit Dogfight