A single number at European roulette has a 1 in 37 chance, so the fair payout would be 36 to 1: paid that, you would break exactly even over time. The game pays 35 to 1, and that missing unit is the entire 2.70% house edge. Every casino bet can be audited the same way: find the real probability, compute the fair payout, compare it to the paid one.
One bet on this site pays true odds exactly: the odds bet in craps, which is why it carries no edge and why it is only reachable behind a bet that does not. In betting markets the same gap appears as the bookmaker's margin, visible when the implied probabilities of all outcomes sum past 100%.
Why it matters
True odds turn the house edge from an abstract percentage into something you can recompute yourself on any bet: the difference between what an outcome is worth and what the game pays for it.
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