Roulette is a casino game in which players place bets on a single number, various groupings of numbers, the colors red or black, whether a number is odd or even and if it is high (19-36) or low (1-18). Players make their bets by placing chips on a roulette table (aka layout) and the dealer then spins the wheel and drops the ball into one of the betting compartments. Winning bets are paid out according to their odds.

A roulette wheel consists of a solid wooden disk slightly convex in shape and with thirty-six metal divisions, called frets or pockets by croupiers, around its rim. The compartments, painted alternately in red and black, are numbered non-consecutively from 1 to 36 with a central division, colored green on European wheels, carrying the sign 0, while American wheels have an additional two green compartments labelled 0 and 00.

Before the wheel is spun, players place bets on what number they believe will come up by laying their chips down on a special betting mat. Bets placed on six or less numbers are called “Inside bets”. Those placed on more than twelve numbers are termed “Outside bets”.

The exact origin of roulette is unknown, although many fanciful stories exist. The French mathematician Blaise Pascal claimed to have invented it in the 17th century, although the game is believed to have been derived from ancient Chinese games such as hoca and portique before being modified by Dominican Monks who brought it to Europe.