Roullete (also roulette and rouleau) is a casino game in which players place bets on which number or group of numbers the ball will fall into as it spins around a revolving wheel. Bets may be made on a single number, various groupings of numbers, the color red or black, or whether the number is odd or even. The game emerged in the 18th century and became a popular fixture in European casinos and gambling houses. It was derived from the earlier games hoca and portique. Fanciful stories claim that it was invented by 17th-century French mathematician Blaise Pascal or by Dominican monks. Its popularity spread to the United States with the arrival of French-style gambling dens. Roulette is a simple game with surprisingly deep strategy and high rewards, but the rules are easy to understand.
The croupier spins a solid wooden or metal disk slightly convex in shape with one or more numbered compartments, called frets by the croupiers and canoes by roulette players. The numbers, painted alternately in red and black, are arranged nonconsecutively from 1 to 36. A 37th compartment, painted green, carries the number 0. On American wheels two green compartments, 0 and 00, appear on opposite sides of the disk.
The dealer places the ball in the spinning wheel and the wheel, and bets are placed on which number or type of number the ball will land on when the wheel stops. When a winning number is determined, the croupier clears all losing bets and pays the winners. To minimize the house advantage, it is advisable to start with bets on groups of numbers rather than individual digits. Players should also set a budget before playing and stick to it.