Humble Pi: When Math Goes Wrong in the Real World

by Matt Parker

The programmers of Excel claim they are not directly to blame. They adhere to the IEEE’s standards for arithmetic done by computers, with only a few minor variations in how they handle unusual cases. The IEEE set out standard 754 in 1985 (most recently updated in 2008) so everyone would agree how computers should ideally deal with the limitations of doing math with finite-precision binary numbers.*

Imagine you’re planning a schedule. What would you do if you needed to know how many fortnights there are in seventy-five days? Most people would reach for a calculator app. But I can guarantee that you are better at solving this problem than a calculator.