Of all the ideas we’ve forgotten from math class, the most important to relearn – because it illuminates our most urgent challenges – is the difference between arithmetic and geometric progressions.

In the investment world, it’s common to discuss average rates of return. It’s not sufficient, however, to simply add up historical returns and divide by how many there are. The proper way to calculate ...

Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...