Tossing Jokes

A candidate brought dice into the examination hall for MCQ. He started tossing the dice to select his answers. The superintendent just gave a glimpse at this candidate, as he passed by, as it is common to have students trying their luck. Very soon the candidate finished his whole paper and slept on his table. Half an hour later, the candidate sat up, and started tossing the dice again The superintendent felt curious, and approached the candidate.
Superintendent: "Gentleman, why are you tossing the dice again, since you've already finished all the questions earlier on?"
Candidate: "Sir, I have to double check my answers"