# How much of the content from past classes do people remember? [closed]

I'm currently a third year math student and I am preparing to take my GRE subject test. As I study for the test I feel as if I have forgotten much of the content from classes that I've taken in the past. I did well in all of these classes but I find myself having to go back and relearn things from DE, Linear algebra, Number Theory, etc. Is this common for math students or am I dumber that I previously thought? This whole situation has me feeling pretty low. I'd appreciate any insight.

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This is not uncommon at all. I know professors who couldn't solve problems on old exams they had written for graduate classes they taught a year ago. Don't worry about it. Everything is easier the second time around. –  Potato May 28 '13 at 0:03
There’s a good bit of truth to use it or lose it; things that you once learned but have since had little occasion to use are quite likely to have become fuzzy in memory or even been lost completely. Whenever I went several years without teaching Calculus III, I had to relearn some of it. –  Brian M. Scott May 28 '13 at 0:03
This is a good argument for discussing with and/or tutoring younger students material you've studied. It will also ultimately make you a better teacher in grad school and after. –  Ted Shifrin May 28 '13 at 0:06
When I was in school, it was my experience that I didn't really understand the material from course $n$ until I used it in course $n+1$. –  vadim123 May 28 '13 at 0:07
I didn't do or teach any serious Algebra in close to 10 years now, and last year I had a student asking me help with some problems in group theory. I remembered that in highschool I used to solve those type of problems in minutes, it took me much longer now.... –  N. S. May 28 '13 at 0:07