There’s a reason why jackpots have been growing larger and larger in recent years. The reason has nothing to do with bad luck or crooked lottery officials, but rather basic math.

In the early days of modern lotteries, jackpots were much smaller than they are now. Lottery operators realized that huge jackpots drive ticket sales, and get a lot of free publicity on newscasts and websites. So, they lengthened the odds of winning to make it more difficult. That’s how Powerball and Mega Millions grow to such eye-catching levels.

The key to winning is the numbers you choose. Many players pick birthdays, or numbers that are important to their family and friends. But this is not a good strategy, according to a professor at Duke University. He told WRAL that you’re actually 300 times more likely to be hit by lightning than win the lottery.

Another trick is to use the “Power Play” option on your tickets, which adds a second chance to win the jackpot. But even if you choose all the right numbers, the chances of winning are still mind-bogglingly low.

And if you do happen to win, it’s best not to tell anybody. Most states don’t let you be anonymous, but keeping your name out of the paper and telling as few people as possible can keep you from being inundated with vultures or long-lost relatives. And don’t forget to document your win: make copies of both sides of your ticket, and lock it somewhere only you can access.