I knew that at some point.

As I'm a rising sophomore and will be taking precalculus in September, I have to do a summer math packet. Obviously it's going to encompass a lot of what we learned from Algebra 2.
Now, I don't know about you, but I cannot remember anything I learned more than a year ago. I remember learning it--I have memories of sitting in math class in eighth grade, taking notes, doing problems, and making up codes and ciphers with Kate--but I couldn't tell you how to do anything we actually did, except for the secret codes, which were frankly brilliant. So now, bereft of any sort of algebraic knowledge I once had, I once more have to look up the "Homework Help" videos that got us all through eighth grade. (Thank heaven for Dr. Burger.)
Which makes me think. How much is an education worth if we can't remember any of it? My sister Grace just finished fifth grade, learning the same stuff that I learned in fifth grade, and every time she brought up schoolwork I'd say something like, "Huh, I remember learning that, but I don't remember what it is." I think this proves that if you don't use knowledge, you'll lose it.
I expect precalc will be really hard. I don't even know what it is--I mean, algebra is math with variables, geometry is math with shapes, and calculus is just calculus, but what's precalculus? Yikes. I guess I'd better reread the textbook.