Roullete, or Roulette as it is sometimes called, is a casino game in which players make bets on which number or grouping of numbers they think the ball will land on when the croupier throws a ball into the spinning wheel. Winners are rewarded according to the odds of their bet. It is a very popular game in casinos, and has several variants. The game is thought to have been invented by a French mathematician, Blaise Pascal in the 17th Century. It is also believed to be a descendant of the older games hoca and portique.

Bets are placed by laying chips on a special table mat, with the precise location of each chip indicating the bet being made. Bets on individual numbers are referred to as inside bets and those on other groups of numbers such as red-black, odd-even, or first, second and third dozen are outside bets. Prior to the croupier throwing the ball into the wheel, players can still make additional bets. Once the winning bets are determined, any losing bets are removed from the table and the dealer clears the betting area.

Before the game begins, the croupier will explain how much each of the chips will be worth. Then the player will place his or her chips on the desired spots on the table. Depending on the size of the table and the betting limits, the player can choose from different types of bets. The most common is the straight-up bet, which requires the player to select one number on the board. Another bet is the split bet, which places a wager on two numbers on the board. Finally, the street bet places a wager on three numbers in a row.

Once the bets are made, the croupier will spin the wheel and the ball will land on a number. If a bet is a winner, the winning amount is paid to the player, and the other bets are removed from the table. The player can then make new bets on the next round.

The house edge of roulette is the difference between the payout odds and the probability of winning a particular bet. It varies from game to game, but the house edge is lower on European wheels than it is on American ones. The game is also available with a variety of side bets, which further reduce the house edge. Some games even offer rules such as la partage, in which an even-odds bet that loses to a zero pays out half of its original stake. This can drop the house edge to just 1.35%. This is considerably lower than the average house edge of other casino games. However, it should be noted that even the best systems cannot guarantee a profit. Moreover, the player should always play within his or her bankroll.