The Trick: Assuming an approximately 9% sales ... The rule of 72 comes from manipulating the basic mathematical formula for calculating compound interest. The exact number you need to divide ...

Fortunately, these easy-to-remember math tricks will be your best friend next time you're faced with a tricky equation and ...

However, if you have somehow burnt through all the inventive and corny confession ideas, there’s a new mathematical expression you can use: 128 √e980. This seemingly-random numeric expression, dubbed ...