One of the quirks of roulette games that have both 0 and 00 – the common arrangement in the United States – is that the five-number bet on 0, 00, 1, 2 and 3 has a higher house edge than other wagers. If you make that five-number bet, the house edge is 7.89 percent. On everything else, it’s 5.26 percent.

That prompted a reader to email, asking if there was something special about those numbers that caused the higher edge.