If I could change something in my previous science classes, it would have been the fact that I struggled in the question concerning exponents. It was simple one, but I don't know how I didn't understood that. For example, if there is a question with a calculation "xy²", then I would first multiply x and y, and then calculate the exponent. I did 3 of the questions wrong because of this, it was when I was in 7th grade. I wish I had not done this kind of silly mistake. I an in 10th grade and understand it well now, though.