Poker is a mathematical game, or at least has an element of math. You want to push your chips into the pot when you’re offered positive expectation, and avoid committing chips when you’re a mathematical underdog.
To get a way from situations where you got hold of the wrong end of the stick, a little thing called pot odds might help you.
How to calculate pot odds
Pot odds are the ratio of what’s in the pot and what you have to pay to carry on with the hand. Say that there’s $60 in the pot, and someone bets $60, you have to call $60 to win $120. This gives you the odds 60 to 120, or 1 to 2.
Now you know that if you win the hand more often than one time in three, you will gain money by continuing.
You can then compare the pot odds with the chance of completing draws.
Odds for common draws (approximately)
Gut-shot straight draw 1 to 11
Open ended straight draw 1 to 5
Flush draw 1 to 4
If you were in the pot described earlier, and were offered 1 to 2 on your call, you should fold if you only held a flush draw. But say that your opponent bet $10 into the $60 pot, you should at least call.
However, you can sometimes call even though you’re getting insufficient pot odds. But then you have to know that your opponent is willing to pay you off if you make your hand; otherwise, strictly follow the odds you’re offered.