When a lottery prize gets big, there are often lots of questions about the odds and how it works. Here are a few things to know before you buy your tickets:

Lottery prizes come from ticket sales. The more tickets people buy, the larger the prize.

In the United States, most states have a lottery. There are several different kinds of games, including scratch-off and drawing-based games. People can choose their own numbers or buy “quick picks,” which let the machine select a random set of numbers for them. Some people like to choose numbers that are significant to them, such as birthdays or ages of their children. However, Harvard statistics professor Mark Glickman says these choices decrease your chances of winning because you would be sharing the prize with anyone who also bought those numbers.

While some people might play the lottery simply because they like to gamble, research shows that lottery players are disproportionately low-income and that state lotteries are a hidden tax on those who can least afford it. Many people are still under the false impression that it is possible to win a fortune by buying a lottery ticket, but it is important to remember that the odds of winning are extremely low and that gambling can be addictive. Instead, it’s best to save money and invest in your future. The Bible teaches that we ought to work hard and earn wealth through diligence, rather than through lottery winnings (Proverbs 23:5; Proverbs 12:24). Khristopher J. Brooks is a CBS MoneyWatch reporter covering the U.S. housing market and the business of sports.