Roullete is a casino game that involves spinning a wheel and betting on the color or numbers that will appear. The game was invented by a 17th century French mathematician named Blaise Pascal, who claimed to have developed it while searching for a perpetual motion machine. The game was widely adopted in Paris, where it became a staple at many gambling houses and casinos.

Before the wheel is spun, players make bets by placing chips on a betting mat. The specific locations of the chips on the mat indicate the bet type. The bets on a single number or a grouping of numbers are called Inside bets, while those on odd-even, red-black, first, second and third dozen or the high-low or columns are Outside bets.

A roulette wheel is a solid wooden disk, slightly convex in shape, with compartments around its edge that are painted alternately red and black. Thirty-six of these compartments are numbered nonconsecutively from 1 to 36, while a green segment on European-style wheels carries the sign 0 and two additional green compartments are marked with 00 on American roulette tables.

Roulette is played by a croupier who spins the wheel and throws a ball into one of the compartments. When the ball lands in a number, players who have placed bets on that number, section or color are paid according to their betting odds.

While the house has a slight advantage in all casino games, professional gamblers can sometimes gain an edge by using prediction methods. The only surefire way to prevent this is for casinos to prohibit players from laying down their bets before the spin. However, this would significantly reduce the amount of play and deter casual gamblers, so casinos continue to pay a premium for those who can predict the outcome of a spin.