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EVERYTHING YOU ALWAYS WANTED
TO KNOW (AND MAYBE DIDNT)
ABOUT ODDS, PERMUTATIONS
AND RETURN ON INVESTMENT
WHAT ARE CARD ODDS?
If you havent already noticed, probability is a huge factor in Texas
Hold 'em. For example, there are 2,598,960 possible hands in a 52-
card deck but only 4
Royal Flushes. If the average serious poker
player is dealt 100,000 hands in their lifetime, they will never hold
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(on the first five cards) more than 4 percent of all the possible
hands. And likely a lot less.
Figuring out straight card combinations for the purpose of this text
are called Card Odds (you will be introduced to other kinds of
odds later). Card Odds can reveal some quite interesting information.
For example, how many pat
Straight Flushes will you see in your
lifetime? To determine that number, the expected number of hands
that could be dealt during your lifetime is estimated by the
following calculation:
10 complete poker hands / hr. x 5 hrs. / game x 50 games / yr.
x 40 yrs. / poker life = l00,000 hands of poker per lifetime.
This is a pretty aggressive estimate, as most people will never
come close to this number of
Complete Hands in Texas Holdem.
Based on this level of play, the number of pat (on the first five
cards) poker hands that you should get during your lifetime is
calculated from the card odds and tabulated as follows:
Cards Dealt Number of Pat Hands
No pair 50,000
One pair 40,00
Two Pair 5,000
Three Of A Kind 2,000
Straight 400
Flush 200
Full House 170
Four Of A Kind 25
Straight Flush 1.4
Royal
Straight Flush 0.15
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So statistically, you should see a pat
Straight Flush on your first
five cards once or twice during your lifetime. Most average poker
players will never see even one.
Card players often talk about having a lucky streak or a run.
Mathematically, streaks dont exist. But suppose you did have an
amazing run of cards one evening. What would the odds be of
having five consecutive
Straight Flushes in a row?
Royal Flush 4 .0000015391
Other Straight
Flush
36 .0000138517
Four Of A Kind 624 .0002400960
Full House 3,744 .0014405762
Flush 5,108 .0019654015
Straight 10,200 .0039246468
Three of a
kind
54,912 .0211284514
Two Pairs 123,552 .0475390156
One Pair 1,098,240 .4225690276
Nothing 1,302,540 .5011773940
Total 2,598,960 1.0000000000
In every 1.7x1024 deals . . . or once in every
700,000,000,000,000,000,000 years. Youd have to read those cards
in the dark though, because our sun will be long gone by that
time.
Players use card odds to make playing decisions. A decision made
without taking into account card odds makes poker a guessing
game. The chances of finishing a flush or a straight, the probability
of getting an over card (face card), the percentage of times you're
going to flop a card to match your pocket pair - are all extremely
important factors in Texas Holdem.
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Knowledge of these statistics is key to winning.
Here are some other basic probabilities that you should know
about:
You need one more heart to make your flush on the turn
or river - 35%
Probability of hitting an open-ended straight draw (i.e. 4
straight cards, need one on either end to hit on turn or
river)- 31.5%
Probability of being dealt suited cards: 23.5%
Probability of hitting a three or
Four Of A Kind at the flop
when you hold a pocket pair: 11.8%
Probability you will make a pair at the flop, holding two
unpaired cards in the hole: 32.4%
Probability of being dealt AA: .45%
Probability of no one holding a specific card, by number of
players, assuming you do not have that card, by number
of total players.
2 - 84.5%
3 - 70.9%
4 - 59%
5 - 48.6%
6 - 39.7%
7 - 32.1%
8 - 25.6%
9 - 20.1%
10 -15.6%
Probability someone else does not have an ace, assuming
you do have an ace, by total number of players:
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2 - 88.2%
3 - 77.5%
4 - 67.6%
5 - 58.6%
6 - 50.4%
7 - 43%
8 - 36.4%
9 - 30.5%
10 - 25.3%
HOW ARE THE ODDS CALCULATED?
Lets look at the example of having 4 outs (four cards you need to
make your hand). Say you're holding 6c 7d and the flop comes 9s
10h Kc. In this case you need an 8 to make the straight. Since there
are four 8s in the deck, you have 4 outs.
YOUR POCKET
THE FLOP
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ODDS WITH ONE CARD TO COME
Calculating the odds with one card to come is relatively
straightforward.
When you're looking to make the
Inside Straight, you have four
outs. There are a total of 46 unknown cards (52 minus the 2 cards
in your hand minus the 3 cards for the flop and the 1 turn card). 42
of the cards don't make your hand and four do. 42:4 or 10.5:1 =
about 9%. I prefer to use the percentage as it helps when
calculating Pot Odds (to come later).
ODDS WITH TWO TO COME
To calculate the appropriate odds with two cards to come, you
must first determine the total number of two-card combinations
possible after the flop.
The easiest way to calculate this is by multiplying the number of
cards available for the turn (47) by the number of cards available
for the river (46) and dividing that number by 2 (because a card
can't match itself). 47*46/2 = 1081.
A certain number of these 1081 two-card combinations will have
eights in them. To determine odds properly, you need to calculate
two more figures.
EIGHTS ON BOTH THE TURN AND THE RIVER
One of the four eights can appear on the turn. And if one does,
there will be three left for the river. If you multiply 4 by 3 and
divide by 2 (because a card can't match itself) you see that there
are six unique pairing of 8s.
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EIGHTS ON THE TURN OR RIVER
If an eight comes on the turn, there are 46 unseen cards remaining.
But you're no longer interested in the three remaining eights, so
you can subtract those. This leaves 43 unseen cards that will make
a unique pair with one of the eights. Multiply 4 (the number of 8s
in the deck) by 43 (the number of unseen cards) to arrive at 172.
FINISH THE CALCULATION
172 plus 6 comes to 178 -- the total number of two-card
combination that have at least one eight in them and as many as
two eights.
Out of 1081 possible two-card combinations on the turn and river,
178 of those combinations help us make our hand. Subtract 178
from 1081 to find the number of combinations that don't make the
straight (1081-178=903).
The odds against making a straight by the river are: 903:178, or
20%.
What About The Cards The Other Players Are Holding?
Ever wonder why we never factor the opponents' cards or the
Burn Cards when figuring out how many cards are left?
The reason is that we only consider ?unseen cards?. If you saw
what the
Burn Cards were, or an opponent showed you his hand,
you would know that those cards are not going to be drawn and
could use that. We typically do not know what they have, so we
don't even think about it when talking about odds.
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For instance, take a standard deck of 52 cards, remove 2 Aces and
burn 25 of them. If you drew the next card, what are the chances of
it being an Ace? It would be 2/50 (2 Aces left out of 50 unseen
cards). It would NOT be 2/25 just because you burned half the
deck. Okay, do the same thing again, but this time you get to look
at the
Burn Cards. Let's say that of all the cards you burned, none
were an ace. Now your odds are 2/25 because there are still 2 Aces
and now only 25 ?unseen cards?.
You will find that you can easily remember a few of the most
common situations for outs such as the four flush or straight draw
but there has to be an easier way than memorizing the figures for
every number of outs. The good news is that there is a way to get a
good estimation of the odds without the heavy math and you can
also use handy odds charts.
WHAT HANDS WILL WIN THE POT?
The following are the most valuable starting hands in Texas
Hold'em. This chart assumes a medium to loose $5-10 Texas
Hold'em game. The results are based on a computer simulation of
5,000,000 played hands. The percentage shown indicates how
many times in typical game that these hands win the pot.
2 Pair 31%
Pair 27%
Three Of A Kind 12%
Straight 9%
Flush 9%
Full House 9%
Bust (nothing) 2%
Four Of A Kind 1%
Straight Flush <1%
Royal Flush <1%