What to include when your question involves arithmetic — that is the question, and I have not found it answered plainly anywhere I have looked.
Question in the title. Context below, and I have tried to include the things people here always have to ask for.
What I have already read: the relevant maintained document, the two topics it links to, and the tag page. What I could not find is the specific case I am in, which may simply mean it is uncommon.
I am happy to be told this is answered elsewhere if someone can point at where.