A casino is a gambling establishment that offers a wide range of games of chance and, in some cases, skill. Players place bets using chips that represent a value, such as $1, and win or lose money according to the odds of the game. The house has a mathematical advantage over players, known as the house edge or vigorish. Those who possess sufficient skills to eliminate the house edge are called advantage players. The casino makes its profit by taking a small percentage of all bets placed, called a vig or rake. The house edge in a particular game is typically very small, less than two percent, but it adds up over the millions of bets that are placed each year by casino patrons. The vig provides the profits that allow casinos to build towers, fountains, replicas of famous landmarks and elaborate hotels.
Although some gamblers consider the vig to be an unfair business practice, most gamblers understand that it is inevitable and part of the cost of gambling. In order to offset the vig, casino patrons are given complimentary items or comps; these may include food, drinks, hotel rooms and tickets to shows. The amount of time a person spends at the casino and the size of his or her bets determines whether a patron receives comps.
A number of technological innovations have improved the security and supervision of casino games. For example, video cameras have replaced human surveillance, and betting chips have built-in microcircuitry to allow the casino to monitor the exact amounts being wagered minute by minute and to detect any abnormalities in the game results. In addition, electronic monitoring systems are used to observe the spins of roulette wheels and dice to discover any deviation from their expected values.