Blackjack is a game where the object is to build a hand with cards that total as close to 21 as possible without going over. It is played with one or more 52-card decks. Face cards are worth 10, cards numbered 2-10 are worth their printed values, and aces can count as either 1 or 11. The dealer gets two cards and must stand (stop drawing cards) or draw (request more cards) based on a set of rules. Unlike other casino games, blackjack is a game where mathematics can play a significant role. If a player follows certain basic strategies, he can reduce the house edge to less than a percent.

In a typical blackjack game, the players sit around a semicircular table that can accommodate varying numbers of players. The table is backed by a chip rack and a dealer, who stands behind it. Most blackjack games are played with seven players, but some can accommodate up to 12 spots.

When the game starts, each player puts a bet in front of him. He then draws cards until he is happy with his hand. Then he signals to the dealer that he wants to stand. The dealer then pays out the bets according to the rules of the game.

The rules of blackjack vary from casino to casino, but most follow the same general principles. The most important ones are:

A dealer must stand on all 17s and hit soft 19s or better. The dealer must also stand on a hard total of 16 or higher against a ten-value card, and must stand on a soft total of 17 or higher against a ten-value or ace-value card.

Some casinos allow players to double down on any two-card hand, but this is not a good strategy for most people. Other rules include:

Insurance is a side bet that the dealer has a blackjack. The bet pays out at 2:1, but the dealer has a blackjack only about one-third of the time. This bet is a bad idea for anyone who does not have direct knowledge or estimations (such as through card counting) of the dealer’s hole card.

Some casinos have reduced the payout on blackjacks to 6 to 5. This is a big mistake, because it increases the house edge and takes money out of players’ pockets. This rule is only in effect in some casinos, so check the rules before you play.