The one I learnt at the dawn of time was BODMAS.

bracket of Division Multiplication Addition Subtraction.

I learnt this in the 70’s early 80’s in South Africa, so not sure if things have changed.

Been using Joplin for ages now. used to use Evernote and was trying to find something to replace it. Joplin fitted that need, and being able to store all the stuff on my dropbox in encrypted format made it great for use on all my devices. Combination of Joplin and Bitwarden is pretty much my secure solution to everything. lol