Math is a lot like language. It describes the outside world in a way that other people can understand, provided you share the same language--or math. Math describes general truths about the world which can be applied to specific situations (e.g. if 2+2=4 then adding two apples to two oranges makes four fruits), but this is also true of some linguistic statements (e.g. if Dr Pepper bottles are maroon then the Dr Pepper bottle you're telling me about must be maroon). So I view math as sort of a special kind of language: one that consists of general statements which are universally true.
Once it's reframed this way, it seems obvious that math was created. The relations which math describes were discovered, but we then created a system, mathematics, by which to codify those relations.
N.B. Haven't actually read the article