Barbie caught a lot of flack back in the ’90s for declaring, “Math class is tough!” Today we find ourselves in the disorienting position of defending her. We recently got a note from an anonymous ...

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.

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.