On average, bingo operations pay out about 75 percent of the revenue they take in. That makes the house edge on bingo one of the highest in the casino, but it's still less than half the house edge on a typical state lottery, which averages a 45 percent payout rate.

The number of possible unique bingo cards — those where no two numbers are the same — is in the millions. But the odds of winning depend not on the number of possible cards, but on the number of cards in play at any given time. That's because in every bingo game, no matter what the pattern, numbers are drawn until someone wins.

Like every business, bingo has its busy days and times and its slow days and times. The fewer people there are participating in a game, the fewer cards there are in play, and the better the odds of winning are for each of those people. If there are 100 people playing bingo, and each of these 100 people is playing four cards, each person has 4 opportunities out of 400 — or a 1 in 100 chance — to produce the winning card. Now let's say there are 1,000 people playing, still playing four cards each. That means there are 4,000 cards in play, and each player's odds of having the winning card are reduced to 4 chances in 4,000, or 1 in 1,000. (These figures assume there are no duplicate cards and the numbers drawn do not create more than one winning bingo pattern.) Simply put, your odds of winning are better if you can play when the bingo hall is not crowded. On the other hand, the prize money will probably be less.

The number of cards you play also affects your odds of winning, but not necessarily in the way you might think. Most of us would assume that we increase our chances of winning automatically by playing as many cards at a time as possible. Theoretically, this is true. But remember that bingo numbers are called at a fairly fast pace, and if you can't keep up because you have too many cards in front of you, you're more likely to miss a potential winning pattern than to claim a big prize.