From the flashing lights of Las Vegas to the crowded pai gow tables of Chinatown, casinos are found all over the world. Though musical shows, lighted fountains and lavish hotels help draw in the crowds, gambling games are what drive casinos’ profits. Slot machines, blackjack, baccarat, roulette and craps are among the games that provide billions in annual revenue for casino owners.

While some of the thrills of casinos come from their glitz and glamour, they also offer a range of perks designed to reward loyal customers. Many casinos offer “comps” such as free hotel rooms, meals, show tickets and limo service. During the 1970s, casinos in Las Vegas became famous for offering deeply discounted travel packages and cheap buffets to get gamblers to spend more money. The strategy worked: During that decade, more than 51 million people visited casinos in the U.S.

Casinos rely on gaming mathematicians to keep track of the house edge and variance for each game they operate. They use these calculations to determine how much profit they should expect to make and what kind of cash reserves they need in reserve. Gaming mathematicians are sometimes called gaming analysts or vigilance officers.

In the modern casino, a centralized security room with bank of cameras provides an eye in the sky. Video feeds can be adjusted to focus on suspicious patrons and can be recorded, so that if there’s a crime or a cheat, the casino has the evidence to catch the culprit. Casinos also monitor the monetary flow of their customers through different payment methods, preferring those with lower transaction costs.