In MS Word you can highlight a list of numbers separated by paragraph returns, then issue the Calculate command and it’ll add them up and put the result in the clipboard.
You can also do other arithmetic: put numbers in parenthesis to subtract them from the list, use * to multiply, and / to divide.
I see the command in the Tools menu (maybe it imported it from Word?), but it doesn’t seem to do anything.
Does this command exist in LibreOffice? You can just copy the numbers into the macOS Calculator and do the same thing, so if not it’s not the end of the world, but it is convenient - especially during tax season.
TIA