I don't think it's math, but maybe just particular subjects. I say this because I'm horrible at math, but good when it comes to languages. In my English class, the teacher actually went over subordinators and coordinators. I'm thinking, "This is college. Surely everyone in this class should easily be able to know when it's appropriate to use "because," "so," "therefore," "however," etc.'" Boy was I wrong. Out of the 20 some students, only 2, including me, had no problems with this. I didn't understand it. Were not learning Japanese here. This is English; the first language 80% of the students in this class learned. There's no excuse. I'm sure many of you will say the same about math.