Hippo quoted Double entry by Jane Gleeson-White
A fascinating exploration of how a simple system used to measure and record wealth spawned …
The Pythagoreans divided mathematics into four subjects—arithmetic (or numbers absolute), music (numbers applied), geometry (magnitudes at rest), and astronomy (magnitudes in motion)—with geometry as the cornerstone of all education
— Double entry by Jane Gleeson-White (7%)
Didn't expect to see music in there as a mathematical discipline, although it somehow makes sense and, if you think about it, isn't all that surprising! It shows how our categorisations are always arbitrary and could be different if we looked at them a different way.
Later in the book is also mention of how mathematics made its way into art (which makes sense too, because perspective and all)