Do you think I should take a chance on this guy and talk to him?

[I'm so curious]

m just wondering. I always look at the guy I like whenever I see him most of the time. mostly he looks back and facing me . Sometimes his friends watch me. Hes smiled at me a couple of times in hall as we were both eating a sandwhich he was smiling at me as we were both eating. Then he was with his friend and they were facing me looking at me talking smiling. He purposely walked into me a couple of times on was more obvious was a really obviously that it was purpose I walked down the hall he was with friends and was close to my side as I got nearer he moved right out on the my side then when we walked past .He doesn't do this alot. I left the gate he was standing there,and turned his direction I was behind him and he turned around and saw me an smiled .As he was walking towards class I looked at him when I saw him he looked at me as soon as I looked at him for a second then looked away looked in each others eyes( I think) he looked my direction not smiling I noticed his eye colour this time then he turned and carried on walking straight I know it sounds stupid lol but I never really look close at him I mainly only do the looking away without smiling though other times I try to avoid looking at him because I know hes looking. Nearly everytime I see him i will look at him even if its only for a second. so the only thing I really do is look at him . Oh and hes leaving school in 2 weeks we don't know each other
How can I ask him for his number if I talk to him without being creepy?
So can you sense if a girl likes you without speaking to her? and from what I do would you think I was interested in you? Do you think this guy senses I like him? thanks