Ms. Cornelius (an anonymous AP History high school teacher):

All of my grades are based on percentages. I’m not one of these teachers who wants to convert someone’s scores in my head, so I just weight grades differently. But all grades are based on 100 possible points. I can tell at a glance how a student is doing this way.
But this habit often makes it interesting when students are trying to figure out their grades on quizzes. I usually have a rather simple number of questions in terms of being able to calculate grades easily: 5, 10, 12, 20, 25, or 33 items. As I watched several of my AP students struggle with figuring out their grades, I had to suppress a groan of frustration. It was a 20 item quiz– therefore each question would be worth 5 points, right? Young Frederick wanted to pull out his calculator to figure out what his score would be if he missed 7.
“No calculator. You can do this,” I urged.
He couldn’t begin to figure out how to determine his grade without a calculator. He is 16 years old and taking pre-calculus and other college-track classes (I never took a course beyond algebra 2, much to my chagrin). He doesn’t immediately know that 7×5=35, and then subtract 35 from 100, nor can he figure out that 13×5=65. As a matter of fact, he stumbled over the 100-35 part and insisted the answer was 75.
It is obvious that his only problem is NOT that he didn’t do his reading for my AP US history class carefully enough last night. His problem begins with a basic innumeracy. Of course, many would say that he is a victim of a larger educational trend which I pray to God is finally being placed on the pyre of idiotic educational theories: that rote memorization is bad, bad, baddety bad bad.