To calculate the probability of certain outcomes in Blackjack, you begin by understanding the basics of the game and the composition of the deck. The probability of specific hands involves assessing the ratio of favorable outcomes to the total possible outcomes. Factors include the number of decks in play, the cards that have already been dealt, and the value of the cards in hand. By analyzing these elements, you can determine the likelihood of drawing a specific card or achieving a certain total, like a blackjack or busting.