You know what’s often missing from math class? Yes, candy bars, but even more important than that: coherence.

Math class shouldn’t be a mishmash pile of facts, thrown together haphazardly, like an academic version of *The White Album*. It should be a perfectly interlocking tower of truths, climbing upwards with singular purpose—an academic *Sgt. Pepper* or *Abbey Road*.

A good class isn’t a greatest hits record. It’s a concept album.

In that spirit, I’ve been taking each topic in the secondary math curriculum—algebra, geometry, calculus, etc.—and trying to boil it down to its one-word essence. Here are the rules of the game:

*You must choose a single word to complete the sentence, “[Branch of math] is the mathematics of _____.”*

For example, you might say, “Topology is the mathematics of dinosaurs,” or “Category theory is the mathematics of abstraction,” or “Combinatorics is the mathematics of sadness.” (To be clear, only one of those is remotely accurate; you have my sympathy, combinatorists.)