I am a number above 3,
saying I'm 4 and above and you would disagree;
although I am seen as a very large number,
in a paper fills with squares.
Before I make your head spin,
I will give you a hint;
I cannot find the correct tags for this question,
but everyone abuse me with obsession!
What am I?
1. Some said I'm round as a pi(e), but in a way I'm closer to a knife.
2. One of my favorite game is Tic-Tac-Toe.