I use them pretty interchangeably. To me the "math" as a singular seems weird except as a verb ๐ like each equation has multiple terms in the expression so doing math with maths.
https://nostrcheck.girino.org/media/a43ebb076d18e62383911d77486390b1e2f73e8a76d3c8c8690cf397a9d36d86.jpeg
Just gonna leave this here one more time...
Source: https://web.facebook.com/photo/?fbid=1245970524235822&set=a.230031232496428