What the hell is an oral exam in maths? Never heard of such a thing.
They give you some problems, you get a bit of preparation time and then present your solution on the blackboard.
The night before my final exam in English at school, I was having a night out. A bunch of people were headbanging really close to each other and me and a guy there crashed our heads big time. I think I passed out for a second but I thought I was fine. Didn't tell my parents, went to the exam the next day and somehow managed to score the highest result in class. A few days later I found out I had suffered a concussion.
And they say headbanging makes you stupid...