The French wheel has 36 numbers plus a single 0 the American wheel has 36 numbers plus 0 and 00.
The difference is the 00 featured on the American wheel, which is not placed on the French wheel in use at European casinos. It is one of the mainstays of Monte Carlo and other European resorts. In Europe, on the other hand, roulette draws big crowds. But roulette is in danger of being passed in popularity by newer games such as Caribbean Stud Poker and Let It Ride. It draws more players than baccarat, mostly because the baccarat pits have traditionally been closed to low-budget players. On the grand scale of American casino games, roulette has one of the smallest followings, with nowhere near the popularity of slot machines, video poker, blackjack, or craps. Amy Sussman/Getty Images for the Consulate General of Monaco