Here’s how the Rule of 72 works: Divide 72 by your expected annual interest rate (as a percentage, not a decimal). The answer is roughly the number of years it will take for your money to double. For ...

NPR's Ailsa Chang speaks to mathematician Eugenia Cheng about the Pascaline -- a 17th-century invention credited as the first mechanical calculator.

If you're planning to increase your electrical load by adding a new major appliance, make sure your panel can handle it. Here's how.