Roulette is a casino game in which players place bets on individual numbers, various groups of numbers, red or black, odd or even, and high or low. The game also has a ‘zero’ section on the wheel, which is painted green (on European-style wheels) or 00 (on American wheels). The player wins if his bet lands on the number, grouping, color or other aspect on which he has placed his bet.

Roulette has an extensive history, dating back more than 300 years. The French mathematician Blaise Pascal is credited with having invented it at the end of the 17th century. It was adopted quickly in Europe and became popular with gamblers and casino operators. It was eventually brought to America, where it was adapted to gambling dens and rigged wheels, and grew into the game we know today.

There are many roulette strategies, some of them simple and others complicated. Some work better than others, and they all require a large bankroll, but none can guarantee a win. You should always play within your means and walk away when you are losing.

It is important to understand how a roulette round works. Once all the losing bets are cleared off the table and the winners have been paid, the dealer will announce that betting for the next round is open. This gives everyone time to place their bets before the ball is spun and thrown.

A roulette wheel consists of a solid, slightly convex wooden disk with a metal rim. Around the rim are thirty-six compartments, painted alternately red and black, and numbered nonconsecutively from 1 to 36. The last two compartments are painted green and carry the symbols 0 and 00 on American-style wheels, and a single green zero on European-style ones. The symmetry of the wheel is important to a successful game.