Roullete (also Roulette) is a casino game with a spinning wheel that determines the winning number. The game has many variations, and the odds of winning depend on whether you bet on a single number or various groupings of numbers. You can also place bets based on the colour of the winning number, or whether it is odd or even.

The roulette wheel consists of a solid, slightly convex wooden disk with 36 compartments painted alternately red and black and numbered 1 to 36. On European wheels, there is an extra green compartment labelled 0, and on American wheels two green compartments labeled 0 and 00.

A small ball, made of resin or Teflon, is spun around the wheel and lands in one of the compartments. The wheel spins with a high speed, and the ball rotates with an even greater speed. The ball jumps unpredictably between the different sections of the wheel, and as it moves around, the probability of it landing on a particular number is constantly changing.

In the past, the roulette ball was made of ivory. Today, the balls used are made of synthetic materials that closely resemble the look and feel of ivory. They are a little smaller and lighter, which makes them bounce more unpredictably before they land on the numbers.

Online casinos offer both the European and the American version of roulette. It is best to stick with the European version, given that it has a lower house edge. Some sites offer French roulette, which offers an additional “en prison” rule that improves the house edge to just 1.35%. However, this only applies to even-odds bets that lose to a zero.