There are two types of roulette, American and European. The difference between the two is the number of 0's on the wheel. American roulette wheels have two "0's", zero and double-zero, which increase the house advantage to 5.3%. In European roulette there is only one zero, giving the house an advantage of 2.7%. This means that, in the long run, one loses money nearly twice as fast playing American roulette than European roulette.
The two versions also use chips differently. American roulette uses so-called "non-value" chips, meaning that all chips belonging to the same player are of the same value determined at the time of the purchase, and the player cashes in the chips at the roulette table. European roulette uses standard casino chips of differing values as bets, which can make the game more confusing for both the croupier and the players.
There is actually a third type of roulette wheel in use. It is a hybrid of the two versions described above, and is the only kind of wheel that is legal in the United Kingdom. This wheel has an American (English language) layout and a single zero. When a single-zero wheel is used in the United States, it is almost always this type.
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