A mere twenty minutes ago was the linear algebra final. In brief, he's what linear algebra entails: you do simple things like add, subtract, and multiply. But you gotta deal with a bunch of numbers at once (usually nine [because they like to use three by three matrices]). This drives me crazy. When you're dealing with all these numbers, you're bound to make a silly mistake somewhere. And good luck catching your mistake.
So there I was, trying to evaluate simple determinant, and for some reason I thought that 30*10 was equal to 40. Aurgh!!! Nothing was making any sense. I was stuck trying to solve this quadratic equation that had no solutions. And if I couldn't solve this equation, then I'd need to get the next two problems wrong, because they were based on this equation. So after many long torturous minutes of wasting precious exam time trying to solve this insoluble equation, I went of the teacher and asked him what to do. Said the wise teacher, "You've got the hard part right. Just look more carefully." (He said "got" rather than "gotten" because he's German and speaks British English.)
So I sat down and sweated some more, until the light bulb went off in my head, and I said, "Oh!!! 10*30 is not 40! It's 400!"
I resumed my scribbling but things still weren't making sense. I looked and looked for other simple mistakes, but none were to be found. The teacher saw my frantic squirming and came over to me. "You look like you're in a rut. Continue with the other problems, and get back to this one later."
"I finished all the other ones." said I, "I can't figure out what I'm doing wrong. I already realized that 10*30 is 400 and not 40, but the quadratic still makes no sense."
"Are you listening to what you're saying?"
The light bulb went on again! 10*30 is not 40. Nor is it 400. It's 300!
The quadratic equation suddenly became simple, and everything worked out nicely. I know I got that problem (and the ones related to it) right, but I'm still not so sure about the others. Who knows what other silly mistakes I made without realizing it? If I was nervous enough not to know that 10*30 = 300, then I could have made all sorts of silly mistakes. So I'm sitting tight, waiting for him to post the final grades.