A casino is a building that houses games of chance and in some cases has elements of skill. Craps, roulette, poker, blackjack and video slots are the games that most people think of when they hear the word casino. These gambling establishments have many luxuries to attract patrons, but they would not exist without the games that make them profitable.

The majority of casino revenue comes from slot machines and (since the 1980s) video poker. These games are operated by computers, which dispense money in small amounts and track the game players’ playing habits. These data are useful to casinos, who use the information to award comps to their most valuable patrons. These perks can include free food, drink and shows. In return for these perks, the patrons give up some of their winnings.

To protect themselves against cheating and stealing, casinos employ security workers. The employees monitor the games from the floor and in booths behind the scenes, and they can watch each table, changing window and doorway through cameras mounted in the ceiling. This “eye in the sky” allows security workers to watch suspicious patrons and note their betting patterns, which may signal cheating.

Some casinos also employ gaming mathematicians to work out expected values of various casino games and calculate their house edges and variances. These figures are used to help predict the amount of money a casino can expect to make as a percentage of total turnover and to determine how much cash it needs in reserve.