I gave him my number. When will he call?

There's this guy who comes into my work all the time. I'm not being self-centered, but I think he might find me very interesting and attractive because he stares at me all the time without being a creep about it. It seems like he just really wants to get to know me. I didn't push on too early in case he was only checking me out, but this has gone on for a couple of months now. I finally got the nerve to give him my number yesterday. However, at work I'm too busy to talk, and it's a long weekend. I slid my number to him, smiled and walked away. I think he was waiting to talk to me. I couldn't go over, and I was too nervous to look at him. I'm 21, and I estimate that he's around 32-33. Age isn't a problem for me though. I wish I had given him my number with a bit more "finesse". Am I being paranoid in worrying about how I wasn't very "smooth", and that because of it he won't call? From your POV, what do you think? Go into detail.