The first thing I do with any multi-choice exam paper is write RTFQ, KISS & TLAR at the top of teh page on my answer sheet and keep running the three through my mind with every question.
RTFQ & KISS I'm sure you all know but TLAR = that looks about right. If the answer doesn't look right then it probably isn't. Same theory can be applied for lots of things, a good example being during an inflight diversion. If your new destination is mostly to the north-ish yet your carefully calculated new heading is something like 076 then a quick TLAR check will tell you something is clearly wrong.