When it comes to the number 7 and gambling, it is widely believed that it's the fairest number to predict. In other words, the fairest chance of winning and losing is said to be by guessing a number between one and seven.

Casinos operate under a myriad of rules from both state and federal governments. They are one of the most regulated businesses in the US. Sometimes, when all those regulations aren't met, the casino may refuse to pay you, at least momentarily.