The lower right cell shows a house edge of 10.65%. I do not know what is the most common win, but the following return table shows the odds for a win of 150 to 1. There is also a version of 2G'$ for triple-zero roulette. Divide that by the one-unit original bet and you have a house edge of 5.33% by parlaying, relative to the initial bet. If the player parlays, his expected loss between the two bets is the sum of 1/37 = 0.0270 units from the first bet and an average of (1/37)*36*(1/37) = 0.0263 from the possible second bet for a total of 0.0533 units. Now there are 38 pockets 1 through 36 and two extra zero pockets. The answer has to do with the way the house edge is defined. Here, the Americans modified the game further and devised their gaming style by introducing an extra zero pocket on the roulette wheel (double zero). The astute reader may wonder why the player should accept a win of 1,300, at a house edge of 4.97%, rather than parlay, when the house edge in single-zero roulette is 2.70%. Thus, I would do that rather than accept a win of 1,275 or less. By parlaying a first win on zero himself, the player can achieve a win for two consecutive zeros of 1,296 to 1.
