Can Ace Be High Or Low In Poker

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Sanderson M. Smith

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The ace is 'king' in high-low poker. In the vast majority of high-low poker games an ace may be used as both the highest and lowest card. That makes aces significantly more valuable in high-low poker than any other card and starting hands that include an ace more desirable.

POKER PROBABILITIES (FIVECARD HANDS)

In ace-to-five low poker, where aces are allowed to play as low and straights and flushes do not count against a hand's 'low' status, this is the best possible hand. In high/low split games, it is both the best possible low hand and a competitive high hand. The low ace rule applys for the five high straight flush (also known as the wheel). An ace high straight flush, such as Ad Kd Qd Jd 10d is called a royal flush, and is the highest ranked hand in standard poker, without wild cards. Many home poker players play that straights and flushes count, but that aces can be counted as low. In this version 5-4-3-2-A is a bad hand because it is a straight, so the best low hand is 6-4-3-2-A. There are a couple of issues around the treatment of aces in this variant. First, what about A-K-Q-J-10? There are 13 denominations (A,K,Q,J,10,9,8,7,6,5,4,3,2) in the deck. One can think of J as 11, Q as 12, and K as 13. Since an ace can be 'high' or 'low', it can be thought of as 14 or 1. With this in mind, there are 10 five-card sequences of consecutive dominations. These are displayed in TABLE 1.

In many forms of poker, one is dealt 5 cards from astandard deck of 52 cards. The number of different 5 -card pokerhands is

52C5 = 2,598,960
Can ace be high or low in poker room

A wonderful exercise involves having students verify probabilitiesthat appear in books relating to gambling. For instance, inProbabilities in Everyday Life, by John D. McGervey, one findsmany interesting tables containing probabilities for poker and othergames of chance.

This article and the tables below assume the reader is familiarwith the names for various poker hands. In the NUMBER OF WAYS columnof TABLE 2 are the numbers as they appear on page 132 in McGervey'sbook. I have done computations to verify McGervey's figures. Thiscould be an excellent exercise for students who are studyingprobability.

Can Ace Be High Or Low In Poker Games

Ace

There are 13 denominations (A,K,Q,J,10,9,8,7,6,5,4,3,2) in thedeck. One can think of J as 11, Q as 12, and K as 13. Since an acecan be 'high' or 'low', it can be thought of as 14 or 1. With this inmind, there are 10 five-card sequences of consecutive dominations.These are displayed in TABLE 1.

Can Ace Be High Or Low In Poker Terms

TABLE 1
A K Q J 10
K Q J 10 9
Q J 10 9 8
J 10 9 8 7
10 9 8 7 6
9 8 7 65
8 7 6 54
7 6 5 4 3
6 5 4 3 2
5 4 3 2 A

The following table displays computations to verify McGervey'snumbers. There are, of course , many other possible poker handcombinations. Those in the table are specifically listed inMcGervey's book. The computations I have indicated in the table doyield values that are in agreement with those that appear in thebook.

TABLE 2
HAND

N = NUMBER OF WAYS listed by McGervey

Computations and comments
Probability of HAND
N/(2,598,960)
and approximate odds.

Straight flush

40

There are four suits (spades, hearts, diamond, clubs). Using TABLE 1,4(10) = 40.

0.000015
1 in 64,974

Four of a kind

624

(13C1)(48C1) = 624.

Choose 1 of 13 denominations to get four cards and combine with 1 card from the remaining 48.

0.00024
1 in 4,165

Full house

3,744

(13C1)(4C3)(12C1)(4C2) = 3,744.

Choose 1 denominaiton, pick 3 of 4 from it, choose a second denomination, pick 2 of 4 from it.

0.00144
1 in 694

Flush

5,108

(4C1)(13C5) = 5,148.

Choose 1 suit, then choose 5 of the 13 cards in the suit. This figure includes all flushes. McGervey's figure does not include straight flushes (listed above). Note that 5,148 - 40 = 5,108.

0.001965
1 in 509

Straight

10,200

(4C1)5(10) = 45(10) = 10,240

Using TABLE 1, there are 10 possible sequences. Each denomination card can be 1 of 4 in the denomination. This figure includes all straights. McGervey's figure does not include straight flushes (listed above). Note that 10,240 - 40 = 10,200.

0.00392
1 in 255

Three of a kind

54,912

(13C1)(4C3)(48C2) = 58,656.

Choose 1 of 13 denominations, pick 3 of the four cards from it, then combine with 2 of the remaining 48 cards. This figure includes all full houses. McGervey's figure does not include full houses (listed above). Note that 54,912 - 3,744 = 54,912.

0.0211
1 in 47

Exactly one pair, with the pair being aces.

84,480

(4C2)(48C1)(44C1)(40C1)/3! = 84,480.

Choose 2 of the four aces, pick 1 card from remaining 48 (and remove from consider other cards in that denomination), choose 1 card from remaining 44 (and remove other cards from that denomination), then chose 1 card from the remaining 40. The division by 3! = 6 is necessary to remove duplication in the choice of the last 3 cards. For instance, the process would allow for KQJ, but also KJQ, QKJ, QJK, JQK, and JKQ. These are the same sets of three cards, just chosen in a different order.

0.0325
1 in 31

Two pairs, with the pairs being 3's and 2's.

1,584

McGervey's figure excludes a full house with 3's and 2's.

(4C2)(4C1)(44C1) = 1,584.

Choose 2 of the 4 threes, 2 of the 4 twos, and one card from the 44 cards that are not 2's or 3's.

0.000609
1 in 1,641

'I must complain the cards are ill shuffled 'til Ihave a good hand.'

-Swift, Thoughts on Various Subjects

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