In poker, players make bets by putting chips into the pot, in turn, either to call or raise. When a player says “raise,” they add more chips to the betting pool, and all players must either match that amount or fold their hand. Players may also drop out of the betting round altogether by saying “drop” or by leaving their cards face up in the center of the table.

The first two cards in a poker hand are called hole cards. These are personal to the player and remain hidden from other players. A player can create a winning poker hand by combining their hole cards with the community cards on the table. If more than one hand has five of a kind, the higher card wins (five aces beats five kings, for example).

Although poker involves a large element of chance, it is possible to improve your chances of winning by using probability theory, game theory, and psychology. This is because poker is a game in which it is important to separate the unknown and uncontrollable from what you can know and control.

In the 1970s, a Princeton University mathematician named John von Neumann used his “Theory of Games” to prove that poker could be solved mathematically. This work presaged the rise of artificial intelligence, a discipline that has since made significant contributions to areas as diverse as submarine warfare, auctions, and the way species compete to pass their genes to future generations.