Let's face it, I may have a PhD in Chemistry, but I am still the queen of math errors. In grad school, I was often "off" by a factor of 10, meaning my decimal point got placed at the wrong spot. Brilliant. I cannot stress how colossally annoying it is to make careless math errors only to realize it at the end of an experiment. And of course, last week, I made a doozy in my first batch of blood orange pâte de fruit that I carried through 3 subsequent batches until I realized what I had done. It took me 4 batches of pâte de fruit, and much swearing, until it dawned on me that the amount of sugar I had calculated was half what it should be.
Reminds me of that famous latin quote "Errare humanum est"—to err is human. (Yes, I took latin for 5 years in school and that's pretty much all I remember).