Math question

[RobNottsUk]

You can use basic probability (like outs over 3 cards extending 2 card to come flop to river calcs), for rough calculations. But if you want to be cuter about it, then combinatorics are best.

c(50,3) = 50! / ((50-3)! * 3!) is the number of flop with 2 known hole cards. The number of subset combinations meeting your criteria over your total possibilities gives you the exact probability.

There's a number of books covering the sort of Poker Maths now, I have "Science of Poker" by Mahmoud. I think one of the best ones, has been produced by 2+2 forum users; though I've only skimmed it in a bookshop not read it properly yet.