A lottery is a type of gambling where participants choose groups of numbers and win prizes if their number matches those randomly selected by machines. Some states run their own lotteries, while others contract with private companies to run them for a fee. Prizes range from cash to goods to services such as vacations or automobiles. Lottery games have long enjoyed broad public approval and are an important source of state revenue. They also benefit specific constituencies, including convenience store owners (who are usually the primary vendors); suppliers of lottery equipment and services (whose contributions to state political campaigns are widely reported); teachers, whose schools are often earmarked for prize money; and state legislators, who get used to an extra income stream.

Lottery players typically select a group of numbers that have some personal significance to them, such as the dates of their birthdays or anniversaries. However, it is not clear that such numbers increase their chances of winning. Moreover, playing more tickets does not improve chances of winning and may lead to a split of the prize.

Large jackpots drive ticket sales, but they can become deflated if they are not won. To ensure that prize funds remain high, lotteries typically have rules that require a certain percentage of receipts to cover costs, profit and promotional expenses. This leaves the remaining prizes available for winners.