Online Poker Forum - Math made not so easy by Andy Bloch

 
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wim-np
High Card


Joined: 26 Mar 2009
Posts: 4

PostPosted: Thu Mar 26, 2009 7:23 am    Post subject: Math made not so easy by Andy Bloch Reply with quote

In "Math made easy" Andy Bloch gives two exemples of pot-calculating (timers: 03:54 & 14:13).

03:54
calculation of the not-helping cards:
52 (deck) -/- 4 (board) -/- 2 (your hand) -/- 9 (outs) gives 37 not helping cards.
Andy Bloch states that there are 35 not helping cards.

14:13
calculation of the remaining cards:
52 (deck) -/- 3 (board) -/- 2 (your hand) gives 47 remaining cards.
Andy Bloch states that there are remaining 45 cards.

Would you tell me what math-magic Andy has applied to make these two cards disappear?
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vectorspace
Royal Flush


Joined: 17 Dec 2007
Posts: 918
Location: Texas

PostPosted: Thu Mar 26, 2009 7:31 am    Post subject: Reply with quote

I think Andy's assuming that the villain has a made hand. In that case, the villain's 2 cards would not likely be helpful to your hand since you are drawing.
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feldonkitten
High Card


Joined: 06 Dec 2006
Posts: 13

PostPosted: Mon Mar 30, 2009 9:50 am    Post subject: Reply with quote

I'd like to see Andy or any Pro respond to this because I think OP is right. You are not supposed to "remove" unseen cards, even those in the other players hands, from the deck when calculating odds. I'm going to try to send him a message via his website to ask him to come look at this and reply, I bet he will Smile
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SmellsLikeDonk
Royal Flush


Joined: 12 Jan 2009
Posts: 598
Location: Shoving where it's +EV

PostPosted: Mon Mar 30, 2009 10:25 am    Post subject: Reply with quote

In general I don't think it's wrong to remove cards when you're calculating odds. You might to want to consider the odds for a worst-case scenario ("given that he has this particular hand, what are my odds?")
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19duke84
Pair


Joined: 09 May 2006
Posts: 27

PostPosted: Mon Mar 30, 2009 11:23 am    Post subject: Re: Math made not so easy by Andy Bloch Reply with quote

wim-np wrote:
In "Math made easy" Andy Bloch gives two exemples of pot-calculating (timers: 03:54 & 14:13).

03:54
calculation of the not-helping cards:
52 (deck) -/- 4 (board) -/- 2 (your hand) -/- 9 (outs) gives 37 not helping cards.
Andy Bloch states that there are 35 not helping cards.

14:13
calculation of the remaining cards:
52 (deck) -/- 3 (board) -/- 2 (your hand) gives 47 remaining cards.
Andy Bloch states that there are remaining 45 cards.

Would you tell me what math-magic Andy has applied to make these two cards disappear?


The math eliminates the 2 cards that are in your opponents hand as it is impossible for either of your opponents cards to hit the board (which is an obvious statement; if a player has the As then a As can't come on the turn or river in a normal 52 card deck). That being said there are only 44 cards remaining in the deck in the first example (52 - 4 (flop + turn) - 2 (your cards) - 2 (opponents cards = 44 cards left in the deck). Of those 44 cards 9 are your outs which leaves 35 cards as "not helping".

Andy's math is correct. He isn't basing it on "unseen" cards he's basing it on # of outs compared to the # of cards remaining in the deck under the assumption that your opponent has a hand that doesn't contain any of your outs.
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feldonkitten
High Card


Joined: 06 Dec 2006
Posts: 13

PostPosted: Mon Mar 30, 2009 12:47 pm    Post subject: Reply with quote

Agree, it doesn't hurt to discount some outs, or to be on the "safe side" when deciding if you have the odds to call (as suggested by smellslikedonk) but, but purely speaking of mathematical odds, you only remove exposed cards.... I don't really care to argue it here which is why I am hoping Andy or another Academy pro will explain exactly why 2 cards appear to be missing in the calculation in the video.

Maybe he is considering that the villan has 2 of his outs, but that is not a presumption I see in books about poker, etc. ever so I'd just like to know for sure that is what he was thinking. Discounting the outs for that reason speaks more to hand reading, other reasons you believe him to be holding your outs, etc. and the examples seem to be only about math.

ref. http://forumserver.twoplustwo.com/32/beginners-questions/outs-deck-opps-hand-447095/
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Andy Bloch
Full Tilt Pro


Joined: 22 Jun 2005
Posts: 14

PostPosted: Mon Mar 30, 2009 2:14 pm    Post subject: I was assuming the opponent didn't have one of your outs Reply with quote

I was assuming the opponent didn't have one of your outs, and you could only win with a flush. I think the original graphic showed the opponent's cards but it was changed before the final version.

Anyway, as I point out in the video, pot odds is just a crutch to help you calculate whether calling has positive EV. To calculate EV, you need to put your opponent on a range of hands, and then calculate how your hand does against each hand, and then multiply by the probability that he can have each hand in that spot. (If there is more betting to come, you have to think about that, too.) So, you're calculating your odds against each specific hand, and when you do you remove their cards.

It's not that helpful to say that you have a 9/46 chance of making your flush against a random hand, because (1) your opponent's hand isn't completely random, and (2) when it is random, you don't always win when you make the flush, and you sometimes win when you don't.
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wim-np
High Card


Joined: 26 Mar 2009
Posts: 4

PostPosted: Mon Mar 30, 2009 5:55 pm    Post subject: Reply with quote

I thank you all for your help.
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Yongbae22
High Card


Joined: 16 Apr 2009
Posts: 14

PostPosted: Thu Apr 16, 2009 9:33 pm    Post subject: Reply with quote

Andy Bloch, you're my hero! Obviously we're all human, but funny to think that you would make such an elementary mathmatical error, given your credentials.
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