A lottery is a gambling game in which people pay a small amount of money for the chance to win a larger sum. The prize may be cash, goods, or services. In some countries, lotteries are state-regulated and others are private. Some have a fixed amount for the prize, while in others the value is proportional to the number of tickets sold. The drawing for the winners may be done manually or by computer, but the winning numbers must be determined randomly. A computer is often used because of its speed and ability to store large amounts of data.
Lotteries have a long history in human society. They were used in the colonial era to raise funds for public works projects, such as paving streets or building bridges, and for private purposes, such as buying land or slaves. Benjamin Franklin sponsored a lottery to raise funds for cannons to defend Philadelphia, and George Washington held one to fund his attempt to build a road across the Blue Ridge Mountains.
Lotteries are popular among many people, despite the fact that they have low probability of winning and high costs. In general, lottery purchases cannot be explained by decision models based on expected value maximization, since the purchase of a ticket involves a risky loss and a high discount rate. However, the entertainment value and other non-monetary benefits obtained from playing the lottery can outweigh the cost of the ticket for some individuals.