In my high school library, there was a copy of the classic book “Men of Mathematics” by E.T. Bell. Each chapter is a short biography of a notable mathematician of the past (and yes, they are all men). In the chapter on Carl Friedrich Gauss (1777-1855), I first encountered the famous story of how, as a 10 year old student, Gauss baffled his teacher by instantly solving a problem that the teacher assumed would occupy his student’s an hour or more.

In this post, I will describe Gauss’ insight, then show how a related problem can be solved by using some informed guesswork.

The history of mathematics has many instances where someone has posed a problem for the mathematical world at large to solve, and the problem was not resolved for decades, or even centuries. Often, new mathematics has been discovered in the process of working out a solution.
This post is the story of one such case, the so-called Basel Problem, first posed as a challenge to European mathematicians in 1644. It withstood all attempts to solve it until, in 1734, young Leonard Euler found the answer. As the reader will see, Euler’s solution is a work of astonishing ingenuity, even though the level of the mathematics does not go beyond Algebra I.