Casino Edge on mulitple decks

[JJcoolL830]

I've read that for the basic strategy player who pays no attention to the count and does not vary their bets encounters an increasing casino advantage as the number of decks used increases. Can anyone explain why this is the case since you start with the same ratio of low to high cards as you would in a single deck? Why is a single deck game more advantageous to even the non card counter?

 

[BJStanko]

To complitely explain that it would take some calculations, and it would be probably confusing. Second of all ratio of the cards is not exactly the same as you think, and that is why there is additional change in advatage.

Now if you are in 1 deck game and dealer deals you 2 cards and 2 to himself there are 48 cards left in deck.
In 4 deck game after dealing 4 cards there are 204 cards left in 4 decks.
48/1 = 48 204/4 = 51 51 is not equal to 48,there is a difference of 3 cards so ratio is not the same.

What you need to know is that, with more decks your adventage goes down.

2 decks -0.35

4 decks -0.52

6 decks -0.58

8 decks -0.61

 

[Canceler]

Here's some of the math that might be confusing...

Chances of getting an A, then a T (10-value card) off the top:

1 deck:
A: 4/52 = .07692
T: 16/51 = .31373
Multiplying the two: .02413

6 decks:
A: 24/312 = .07692
T: 96/311 = .30868
Multiplying: .02374

Intuitively, you would expect the ratios to be the same, but as BJStanko said, they're not.