So, if we take the author at his word, then either the teacher had an unwritten rule for the size of the paper, or the student and the author both somehow managed to not read or to forget this rule. If it's a, then rules lawyer the hell out of the idiot teacher. If it's b, then looks like both of them are bad at details and instructions, which is a skill that certainly deserves some attention. So why was that the end of the story?
Probably because it doesn't matter if it was one of the instructions or not, because it's entirely irrelevant to anything other than an arbitrary "follow instructions" assignment. Coincidentally that sort of assignment is precisely what the author complains about.
And reading and writing are irrelevant to whether the kid could do the equations, but if he doesn't have either skill then he needs help, not just for dad to say the teacher is mean. I consider understanding arbitrary rules to be similarly as basic a skill.
