Roulette
House edge

The house average or house edge or house advantage (also called the expected value) is the amount the player loses relative to any bet made, on average. If a player bets on a single number in the American game there is a probability of 1 ⁄ 38 that the player wins 35 times the bet, and a 37 ⁄ 38 chance that the player loses their bet. The expected value is:

For European roulette, a single number wins 1 ⁄ 37 and loses 36 ⁄ 37:

For triple-zero wheels, a single number wins 1 ⁄ 39 and loses 38 ⁄ 39:
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