I went through a box full of random stuff today. One of the things I found was my old graphing calculator from high school. I opened it up and found a surprise - four formulas were written inside the cover, either from Trig or Calculus. But the funny thing to me is that I have absolutely no clue what these mean. They are like a foreign language, they mean nothing to me. But one day not so long ago, I knew exactly what they were & how to use them. Back in the day, I loved me some Calculus! Just a reminder of how much I have changed.