In the United States, 37 states and the District of Columbia (Washington, D.C.) have lotteries. A lottery is a form of gambling that is run by the state. Most states have several different games, including instant-win scratch-off games, daily games and games where you have to pick three or four numbers. But the game with the biggest jackpot is almost always Lotto. This game usually involves picking the correct six numbers from a set of balls, with each ball numbered from 1 to 50 (some games use more or less than 50).

Ever wonder why the lump sum payout amount is about half of the actual jackpot amount, or how to calculate the odds of winning the Lotto? In this edition of HowStuffWorks, we'll learn the answers to these questions, as well as how the ball-drawing machines work and how much money you could expect to take home if you win.