Players only place money into the pot voluntarily, unless they are bluffing other players. As such, the outcome of poker is heavily affected by chance. Therefore, players’ choices in the poker table depend on game theory, probability, and psychology. However, some factors can be controlled, affecting the game’s outcome. For example, the amount of betting before a showdown may be determined by how many players are left in the table.

There are five cards in a poker hand: two cards from each suit plus the five-card community card. If more than one of these cards is higher than the other two, the higher card wins. Poker players tend to be more skilled in poker than non-players, so learning about probability and game theory can help them improve their play. Those who are not interested in playing poker can still benefit from its mathematics. Poker mathematics is fascinating even to those who don’t play the game, since they make mathematical observations about decks and probabilities.

Besides the five-card community cards, poker also has variants such as Three-Card Monte and Spit-in-the-Ocean. All variations of the game will be discussed further in this chapter. For large-scale games with more than 10 players, it’s common to organize two separate games. However, these are not typical in professional poker. These variations are designed to attract and engage a wide variety of players. Once the game starts, players reveal their hands in clockwise order around the table.