Re: I\'m bad at math - help please
Well, many of these probability calculations rely on thinking out the problem clearly. For example, you say in the OP there are 29 low cards left in the deck: true, there are 8 low ranks, four of each rank, so there are 32 low cards in the deck, and three of them are exposed. BUT not all 29 remaining low cards actually help you. Say you have A2 low and the board has a 3, then any A, 2, or 3 will not help you make your low. Just the opposite: those cards will make it impossible for you to make low. So you have five ranks you can hit on the turn (of which 4 cards each exist--20 outs), and once one of those falls, you'll only have four ranks you can hit, (each having four cards--16 outs), so the probability is (20/45)*(16/44)=.16161616...
So start by clearly sorting out exactly what cards you have to hit on the turn, and given what card comes out on the turn, find out exactly what has to happen on the river.
Sometimes it can even be less simple, such as if you are drawing for runner-runner low with A23x in your hand. Say a four is on the board. To keep the draw alive for the turn, you need an A, 2, 3, 5, 6, 7, 8, with three each of A-3 alive (since you have one of each in your hand) and 4 each of 5-8 alive. Now is where it gets tricky. If a 5, 6, 7, or 8 falls on the turn, you have four outs to each of the denominations that DIDN'T fall on the turn, 5-8 (twelve outs), and you have three outs for each of A, 2, 3, so the probability of this event occuring is (16/45)*((12+9)/44) or .17. But your low draw will also stay alive with an A, 2, or 3 on the turn, in which case you must catch a 5, 6, 7, 8 to fill your draw on the river (since A, 2, or 3 will now counterfeit you and you'll be dead), so the probability of this even occuring is (9/45)*(16/44)=.073. And when two events are independent and mutually exclusive (ie they can never BOTH happen at the same time), the probability one of the two occurs is the sum of the probabilities of each event, in this case .17+.072=.242 or around 1 in 4 times. (Note that while this is more likely to occur, I might reccomend chasing running lows even LESS with A23x since A23x hits high board less often than A2xx--ie an 'x' is more valuable than a trey in this case.)
Hope that helps.
-T50
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