In 2021, Americans spent upward of $100 billion on lottery tickets. That sounds like a lot, but in the context of state budgets it’s a drop in the bucket. So while lotteries have been a part of American culture for a long time, it’s worth considering just how much money they really raise and where that money goes.

Historically, people have used lottery to raise funds for all sorts of things, from public works projects to subsidized housing to kindergarten placements. The first European lotteries in the modern sense of the word began in 15th-century Burgundy and Flanders, when towns were trying to boost their defenses or aid the poor.

The idea is simple: You pay a small amount of money for the chance to win big. You pick a group of numbers, or machines randomly spit them out for you, and win if any of your numbers match those drawn in a random draw. The result is that a few lucky winners can suddenly be rich – even though they’re probably not very happy about it in the long run.

There are many different ways to try to increase your odds, from picking the most popular numbers to using astrology or horoscopes. But one of the most interesting strategies is what Romanian mathematician Stefan Mandel calls “grouping.” He explains that if you can find a large enough group of investors, each of whom will invest a very small amount of their own money, then you can buy tickets to cover all possible combinations.