So it turns out it depends on the question, whether or not the last step is mental. I said that with all sincerity the first time.. And turned out, the Prof wanted us to reverse the process and check it out to get the initial numbers. However, in questions requiring doing a list to solve......... the last step is mental. Win for Shelli.
Shelli: Welcome to our ool... There's no need to put the "P" in it.. Let's keep it that way.
Kirby: Hmm...
Shelli: You don't get it?! It's funny. "Pool" "Ool"... No "P" in the pool...
Shelli: ... it's funny isn't it?
Kirby: Sure Shelli, I'm laughing on the inside.
Shelli: Stupes... You're not laughing at all.
So I was having a discussion with a good friend of mine... There was a mix-up with my class schedule and it seems I inadvertently double-booked myself... the following is a snippet from the ensuing conversation... or at least it's conclusion...