It's funny how some teachers and some parents consider students dumb and useless just because they failed an exam. I think it's unfair since intelligence cannot be judge just on a piece of paper.
Yes, exams are not ultimate indicator of examinee's intelligence. Generally, exams are so concentrated around concrete concepts and amount of knowledge fed in the student's brain which is tested in terms of amount of words wrote on paper and use of vocabulary with some other related criterion.