What is 83!?
Stupid answer to a stupid question. It can be used when a student in class is too slow to write something down and has to ask the others to repeat the last part all the time.
After a while you'll get annoyed and you just answer "83!".
It can also be used when someone asks a question of which he could have found the answer if he just thought a little.
dumb student: "What was that last part?"