Game odds are very rarely advertised. Sometimes it is trivial to calculate or simulate the game (blackjack, roulette, craps, video poker) because all of the gam

Game odds are very rarely advertised. Sometimes it is trivial to calculate or simulate the game (blackjack, roulette, craps, video poker) because all of the game parameters are known (i.e. 52-card deck, 38 slots on an American roulette wheel, two 6-sided dice) as are all the payouts. Slot machines, however, are opaque because the probability of hitting any specific combination is unknown to the public. The machine can promise that a 7-7-7 result will pay $5000 but you have no idea how often a 7-7-7 is supposed to hit. Sometimes a casino will take some less popular machines and configure them with an extremely low payout percentage (3% for example) and because the players would not otherwise know this, the casino will put a sign up "97% payout!" to try to attract some value-oriented players, just like a retail store takes old merchandise and puts it in a bargain bin at 50% off.