In the United States alone, people spend more than $100 billion on lottery tickets every year. Many states promote these games as a way to bring in revenue for important public services. But while the public may think winning a lottery is just about luck, there are proven ways to increase your odds of success. Richard Lustig, a former professional gambler and author of “The Mathematics of Gambling,” has some tips for lottery players.

Lottery games are contests based on chance in which a small group wins a prize. They’re not just about picking numbers; they can also be games of skill, such as keno, in which players select groups of numbers from 10 to 80. Lotteries can also involve prizes other than money, such as cars or vacations.

There are some big risks to winning the lottery, though. A surprisingly high percentage of past winners have had some kind of mental breakdown, whether Abraham Shakespeare’s 2006 suicide (covered up with concrete) or Urooj Khan’s cyanide poisoning after a relatively modest $20 million win. But you can take steps to avoid these problems, including setting clear financial goals and assembling a crack team of helpers to manage your newfound wealth.

The lottery is legal in 44 states and the District of Columbia, and six don’t allow it at all: Alabama, Alaska, Hawaii, Mississippi, Utah, and Nevada, whose governments already collect gambling taxes. Critics say that these states’ absences reflect religious concerns, or that they simply don’t see the need for a lottery to raise needed revenues.