multi deck blackjack games

Suppose you took a single deck of cards, shuffled them, and then randomly picked one card. What is the probability that you'll pick an ace? Since there are four aces in a single deck of cards, the chance of drawing one of those aces is the ratio of 4 over 52. Once you draw the ace, you are left with 51 cards to draw a ten-value card. There are 16 ten-value cards in a deck of cards (the four tens, jacks, queens and kings) so the chance of drawing one is the ratio of 16 over 51. If you multiply these two ratios, you will compute the probability of getting an ace followed by a ten-value card in a single deck to be multiple.

For a 6-deck game the chance of drawing the ace as the first card is the ratio 24 over 312. The chance of drawing the ten-value as the second card is the ratio 96 over 311. Multiply the two ratios and you get 2.37%. Double it and you get 4.74%, which is, less than the 4.82% probability of getting a blackjack in a single deck game.

Notice that you'll only be 98% as successful at drawing a blackjack in an eight-deck game compared to a single deck game, which makes the single deck game better. Essentially the effect of removing a card from a single deck affects the percentages of the remaining cards to a much greater extent than in a multiple deck game. This is another important point to remember when you playing blackjack. Although getting more blackjacks is good for the player, it's even better when you get a blackjack and the dealer doesn't. Which brings me to the second reason why the single deck game is better than a multiple deck game, namely the dealer’s chances of duplicating a blackjack is less in a single deck game compared to a multiple deck game. The exact probabilities of the dealer duplicating our blackjack in the same round.