Originally Posted by spentrent

I'll give you an elementary example of a mathematically correct decision:

If you've been playing for a while, you've probably encountered the term "pot odds." This is a basic element of poker that holds no mystical properties, but it factors into all of your decisions-- the pot odds describe the ratio of the current pot size to the amount you have to call to stay in the hand.

Imagine you're in a cash game and a player has pushed all-in on the flop. No one else is in the hand. The flop has 2c7cQd and you're holding AcKc. You're pretty sure that the opponent has at least a pair, so for you to win the pot you'd have to hit your flush draw. The all-in bet makes the pot $300 and you would have to call $100 to stay in. Do you call?

The pot is laying $300 to $100, or 3 to 1 "pot odds." Since the player is all-in, there will be no action after you call this bet. The odds against making your flush on one of the next two cards to come are about 2 to 1.

If you call this bet 3 times, on average you will lose $100 two times and win $300 one time, so you will average +$100 every 3 bets for a positive expectation of $33 per bet. So you better damn well call, or you're LOSING $33 bucks over the long term every time you pass up this opportunity!

This a +EV decision that you can be proud of having made even if you happen to miss your flush in this instance. You see how the pot is laying bigger odds then the odds are against you winning? That's a mathematically correct decision.