TITLE: How do you stay sharp after graduating?
QUESTION [5 upvotes]: So I received my math bachelors back in 2013 and am now in the "real world". But my job doesn't require the upper level math I learned, i'm not in research. My notion is that there are a lot of people in the same position I am where I feel like my core math skills will stay with me for the rest of my life (I'll never forget algebra, geometry, calc) but for some of the higher level math I learned at university, my memory is fading. I did a lot of work on PDEs but I wouldnt be able to solve the simplest problem right now without a reference.
My question is, how do you stay sharp and keep your math knowledge from waning?

REPLY [3 votes]: When Grothendieck died it was discovered that he didn't have not even one mathematical book in his home. He used to say that "Mathematics is to write and not to read". Practice writing Mathematics and you will keep up.