A lottery is a form of gambling in which tokens are distributed or sold, and one or more is randomly selected to win a prize. Unlike games in which skill is required, the outcome of a lottery depends entirely on chance, and a properly run lottery guarantees that each bettor has an equal chance of winning.

The first recorded lotteries were held in the Low Countries in the 15th century, where towns would hold public lotteries to raise money for poor relief and town fortifications. The lottery became popular in the United States in the early 18th century, when George Washington promoted them to pay for the construction of the Mountain Road and Benjamin Franklin endorsed them to help fund the Revolutionary War. During this period, lotteries were widely viewed as an effective and painless method of raising revenue for public usages.

A key element in a lottery is the procedure for selecting winners, and this may take a number of forms. Some lotteries use a pool or collection of tickets or their counterfoils from which the winners are drawn; others require that all the tickets be thoroughly mixed by some mechanical means, such as shaking or tossing, before they can be sorted. Computers are increasingly used for this purpose, as they can store information about large numbers of tickets and can rapidly produce random combinations of numbers that correspond to winning entries. A good way to test a ticket for fairness is to look for “singletons,” which are single digits that repeat on the ticket.