Poker is a card game where players have chips (representing money) to bet with. The game involves a showdown with one or more other players, where the best hand wins the pot. It is a game of incomplete information, and its rules are designed to make decisions based on expected outcomes under conditions of uncertainty. Poker can improve your decision making skills by forcing you to weigh risks and rewards when deciding whether to call or fold.

In the beginning of a betting interval, players usually place their chips into a central pot, which is then raised by one player or more in turn according to the rules of the particular poker variant being played. During this interval, players may also draw replacement cards for their existing ones. The first player to raise and remain in the pot is known as an active player.

During the rest of the game, players can call the raises of other active players in turn, or simply drop out of the pot. A player who chooses to drop out of the pot is considered to have dropped out of any side pots as well. A player who remains in the pot has to continue to contribute at least as much to the total contribution of the players who called the previous raise in order to keep his or her stake alive in the original pot. This is known as matching the method.