A casino is a place where people wager money on games of chance or skill. They also offer hotel rooms, restaurants and entertainment. Casinos range from massive resorts to small card rooms. People play in casinos all over the world. People can even find casino-type game machines in some truck stops and bars.

Gambling has always been a source of revenue for governments, and it continues to be an important industry today. Casinos bring in billions each year for the businesses, investors, and tribes that operate them. They employ many thousands of people. But they can be bad for the communities where they operate, causing shifts in spending from other forms of entertainment and, in the case of compulsive gambling, reversing any economic gains they might have made.

Most of the money that casino patrons lose is not a result of bad luck, but of the built-in advantage that the house has in each game. The advantage can be small — lower than two percent, depending on the game — but over time it adds up. Casino mathematicians and computer programmers determine each game’s house edge and variance, which tells them what kind of profit they can expect to make from a certain game over a long period of time.