Blackjack, also known as 21, is a casino card game that pits you against the dealer. The objective of the game is to accumulate cards that total as close to 21 as possible without going over. Players place bets before being dealt two cards. The dealer then plays their hand based on strict rules. Using basic strategy and learning when to hit, stand, double down, or split can help you win more often than you lose.

Using mathematics to your advantage is the key to success in blackjack. Computer analysis reveals that for every player’s situation and the dealer’s up card there is a play (hit, stand, double down, or split) that has the highest probability of winning. By memorizing these plays and practicing them, you can dramatically reduce the house edge and increase your chances of winning.

When it comes to splitting pairs in blackjack, there are some rules that should be followed strictly. For instance, you should never split eights or aces if the dealer has a 7 up. This is because the dealer has a much higher chance of having a 10 in his hole and you will be losing more money by splitting than you would by just standing.

You should always hit a hand when it is worth 17 or higher, no matter what the dealer’s up card is. This is because a dealer with a 10 in his hole will have a difficult time beating your hand, and you can always hit for more points later on. It is also a good idea to hit when the dealer has a weak card such as a six or five, and this is especially true in face-down games where you can see the other player’s hands.

One of the most important things to remember in blackjack is to keep a positive mindset. This is because both winning and losing streaks are part of the game and how you handle each can have a big impact on your performance. In addition, a positive mental state will help you make better decisions and stay focused on the game.

Aside from the standard insurance bet, there are hundreds of different side bets on the table in blackjack. Most of them are offered by high-end casinos and can be a major source of revenue for card counters. However, they can also be a distraction and cause you to lose track of the main game.

To improve your chances of winning at blackjack, it is a good idea to practice keeping a running count. This is done by taking a deck of cards and turning them over one at a time, adding up the values as you go. You can then divide the running count by the number of decks in play to get the true count, which will give you a more accurate idea of your odds of winning. This will allow you to bet more when the count is high and less when it is low.