E-Betting

I will be in Vegas this coming weekend (my first trip) and I am just getting into sports betting. It makes the games more interesting for me to watch. My question is, online when I bet (I only use a site called freesportsbet) it does all the parlay calculations for me so I can see the payouts for my various bets. Do any of the casinos operate this way? Or will I have to fill out a slip take it to a clerk and have them plug it in? I don't want to take up a lot of their time and look like a complete dumb-ass.

Thanks in advance for the help.