The Rule of 70 is a mathematical formula used to estimate the time it takes for an investment or any quantity to double, given a fixed annual growth rate. This rule is used by investors and financial ...

If you try to withdraw early from just about any retirement plan, you'll be slapped with a penalty—an incentive to leave your money alone and let it build toward retirement like you always intended.

American football's professional and college games may look essentially identical on the pitch, but the rules differ in some important ways. Here are the rule variations every fan should know about.