He applied to real life what our elementary and secondary maths teachers have been drilling into us all the time: Always remember the unit of measurement!
I'm *allowed* (not "aloud") to refer to my notes, planner, etc. at my job and it's not considered cheating. It's real life. We're allowed calculators, computers, etc. in life. Plus, if the teacher allowed it, then it's not technically cheating.
He(?) deserves a pass
Well done Professor for allowing the creative student in.