Is there a keyboard shortcut for the therefore sign "∴" on mac? Or is there a way to create a keyboard shortcut for it?
I found several answers for you here: https://stackoverflow.com/questions/3685146/how-do-you-do-the-therefore-%E2%88%B4-symbol-on-a-mac-or-in-textmate

a google search is all it took.

In the character viewer under math symbols. ∴