Roullete (French: “little wheel”) is a gambling game that involves placing bets on which of the many red and black numbered compartments on a revolving wheel the ball will come to rest in. Players place their bets by laying down chips on a betting mat where the precise placement of the chip indicates the type of bet placed.

Roulette is often believed to have been invented in the 17th century by the French mathematician Blaise Pascal, although it likely grew out of older games such as hoca and portique. By the end of the 18th century, it had become a leading casino and gambling game in Europe.

The wheel consists of a solid wooden disk slightly convex in shape that is surrounded by a metal rim with thirty-six numbered compartments (called frets or pockets by roulette croupiers) alternately painted red and black and numbered nonconsecutively from 1 to 36. On European wheels a 37th compartment, painted green, carries the number 0; on American wheels there are two extra green compartments numbered 00.

Each time the wheel is spun, the ball will drop into one of the compartments. When the dealer announces “no more bets!” it is signalling that the betting for the current round is closed and play will begin for the next round.

In addition to betting on individual numbers, a player can also make bets on groups of numbers that pay off at higher odds. These bets are called “outside bets”. The most common outside bet is on the Dozens, which pays 2-1 and can be made by betting on any of the first 12 numbers. There are other, more exotic, outside bets as well which can be made on the Columns, Odd/Even, or Snake Bets.