Roulette is a game of chance in which a small ball rolls around a wheel and people place bets on the number it will land on. Its history dates back to the 17th century, when it was invented in France by Blaise Pascal. Originally, the game was based on earlier games such as hoca and portique. Today, it is played in casinos and gambling dens all over the world. There are many different theories as to the origin of this game, but no one knows for sure how it came to be.
The game consists of a spinning wheel with several sections affording players various betting opportunities, and in the center of the wheel a revolving dishlike device called a roulette cylinder into which a ball is spun to come to rest finally in one of the compartments. The cylinder contains thirty-six divisions, alternately painted red and black and numbered nonconsecutively from 1 to 36. On European-style wheels, there is also a green compartment that carries the sign 0. On American roulette wheels, there are two additional green compartments marked 0 and 00.
In the game, players bet on which number the ball will land by placing chips on a betting mat. The precise placement of the chips indicates the bet being made. Bets on six numbers or less are termed Inside bets, and those on 12 numbers or more are Outside bets. The croupier then spins the wheel and drops the ball into one of the compartments. Depending on how the wheel and the ball land, the winning bets are paid out and the losing bets are cleared off the table.
There are some interesting symmetries between the numbers on the wheel and their placement on the betting mat. For example, all the low red numbers and all the high black numbers are on one side of the wheel while the second dozen – 29-7-28-12-35-3-26-0-32 – is on the other. This symmetry makes a bet on the second dozen slightly more profitable than a bet on a single number, since it pays 2-1 instead of the usual odds of 1-3.
The range of house edges on roulette bets is not as great as it is in craps, but it is still a significant factor that can gouge gamblers. The best way to minimize it is to play on a European wheel (single zero) and avoid the American 00 and 0 slots. Players can also try to find a roulette wheel that has a bias that no one has noticed yet and take advantage of it. However, even these techniques are not foolproof and can be beaten with practice or just luck. In either case, players should always cash out their winnings as quickly as possible to prevent dipping into them and reducing their chances of getting lucky again. It is also a good idea to avoid betting on numbers that have been hit recently.