I'm bad at math - help please

[Onaflag]

I suck at math, but have read enough 2+2 books over the years to know I suck, but should know it. Is the following correct? I wanted to know the chances of a low in Omaha8 when 1 card on the flop is low and I have 2 good low cards. Or should I just give this up and find odds charts? [img]/images/graemlins/grin.gif[/img]

52 cards in the deck
I have 4 and the flop has 3. 45 unseen cards.

20 high cards in a deck
32 low cards in a deck

I have 2 lows. Board has 1 low.

29 low cards remain and turn brings a low card.

29/45 x 28/44 = 41% chance of a low by the river.

Onaflag..........

[jay_shark]

29/45 = 64.4%
16/45*28/44 = 22.62 %

64.4% + 22.62% = 87.02 %

That is , you'll hit at least one of 29 low cards by the river 87.02 % .

Also , you have to define what you mean by low cards . Do you really think any of these low cards are good ?

[BruceZ]

[ QUOTE ]
I suck at math, but have read enough 2+2 books over the years to know I suck, but should know it. Is the following correct? I wanted to know the chances of a low in Omaha8 when 1 card on the flop is low and I have 2 good low cards. Or should I just give this up and find odds charts? [img]/images/graemlins/grin.gif[/img]

52 cards in the deck
I have 4 and the flop has 3. 45 unseen cards.

20 high cards in a deck
32 low cards in a deck

I have 2 lows. Board has 1 low.

29 low cards remain and turn brings a low card.

29/45 x 28/44 = 41% chance of a low by the river.

Onaflag..........

[/ QUOTE ]

That is the chance of 2 low cards by the river, but that would include giving you a pair or more. If you want to make an 8-low or better, and you currently have 3 different low cards between your hand and the flop, then there are only 29 - 9 = 20 low cards that you can draw on the turn that don't give you a pair, and 16 on the river, so this should be:

20/45 * 16/44 =~ 16.2%.

[T50_Omaha8]

Wrong forum, I know, but....

Just to make things easier, there is pretty much NEVER a situation in Omaha/8 where you should draw to a runner runner low--and I never say never. You should definitely have a flush draw, OESD, or two pair to go along with it--you need to be thinking high if two high cards are on the flop. Backdoor lows merely add a little value to a high draw.

[Onaflag]

[ QUOTE ]
Just to make things easier, there is pretty much NEVER a situation in Omaha/8 where you should draw to a runner runner low

[/ QUOTE ]

You speak the truth, Bro, and I appreciate you piping in here.

I've always ignored the "how" part of the math and relied on memorized odds in HE. When I study Omaha, I read over and over what to do and not to do, but can't seem to find the actual odds of certain events happening. I decided to start with something simple (an event, not a strategy) to determine if I even knew how to perform the calculations.

Then I can crunch the more strategic situations to help internalize decisions.

Ignoring the strategy, if I were a camera above the table watching the action without involvement, did I come up with the correct number?

Thanks for all the replies.

Onaflag.........

[T50_Omaha8]

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

[BruceZ]

[ QUOTE ]
Ignoring the strategy, if I were a camera above the table watching the action without involvement, did I come up with the correct number?

[/ QUOTE ]

No. I already told you why it was wrong and computed the correct answer. Didn't you see it?

[Onaflag]

[ QUOTE ]
[ QUOTE ]
Ignoring the strategy, if I were a camera above the table watching the action without involvement, did I come up with the correct number?

[/ QUOTE ]

No. I already told you why it was wrong and computed the correct answer. Didn't you see it?

[/ QUOTE ]

I did. Thank you very much. I didn't consider pairing which gave me very incorrect results. [img]/images/graemlins/blush.gif[/img]

Onaflag...........