The American roulette wheel has some key differences to the standard wheel you see throughout casinos in Europe and the UK, with 38 numbers (1 to 36 plus 0 and 00). Numbers from 1 to 36 are alternately coloured red and black, while the single zero and the double zero are marked in green. In Europe, the roulette table does not have a double zero. (資料來源 )
A martingale is a class of betting strategies that originated from and were popular in 18th-century France. The simplest of these strategies was designed for a game in which the gambler wins the stake if a coin comes up heads and loses if it comes up tails. The strategy had the gambler double the bet after every loss, so that the first win would recover all previous losses plus win a profit equal to the original stake. Thus the strategy is an instantiation of the St. Petersburg paradox.(資料來源 )