Keno is strictly an American invention that originated in the casinos in Nevada, perhaps in Reno. During the game, twenty numbers from one to eighty are selected at random. Prior to each game at the casino, the player may choose from one to fifteen numbers, or "spots", he thinks will be selected during the game. The player enters, or "marks", the desired spots and places a bet. At the end of each game, the spots marked by the player are compared to the twenty numbers and the payoff is computed accordingly. Keno seems to have a high attraction in Las Vegas because the betting is very simple and the maximum payoff is very high. Nevertheless, the probability of winning is extremely low; indeed, Keno returns more to the house than virtually any other game.