[Tommy]

For those who may not know, there's a difference between the house odds of winning on any particular game and the percentage of the player's money they keep at the end of the day. Here's an example with roulette. The player's odds of winning a simple even/odd bet are 47.4%, or almost 50/50. So if he starts with $100 and makes one hundred $1 bets, he'll win back his own $1 bet plus $1 from the house an average 47.4% of the time. So after having bet the entire $100 once, he'll have about $94 left. But if he keeps betting, on average he'll have less after each round of betting. If he continues for thirteen rounds of betting, on average he'll have about $50 of his original $100 left. If he quit after the first round, the house kept just 6% of his money. If he quit after the thirteenth round, the house kept 50% of his money. If he kept gambling until is was all gone, the house kept it all. Not bad for the house on a game with only a 5.2% advantage.