Although it is legal to play card count in blackjack in america, UK, as well as Canada, we do not advise doing so in an effort to beat the house. Only when the games are played with a small total of cards, as is typically the case in brick-and-mortar casinos, does card counting work. Based on how many cards have previously been dealt, you may keep track of what number of high and low cards are still available if you know how several decks are being utilized.