He Did Not Actually Do Poorly in School
We love to swap ironic facts about famous people, especially in our click-bait-driven Internet culture. So it's no surprise that the notions that Einstein struggled with math and that he failed his college entrance exams have such staying power. In truth, he excelled in physics and math from a young age and studied calculus while only 12 years old. He also knew his way around Greek conjugation and Latin declension. So how did the idea that he failed math gain traction? Possibly because, during one year of Einstein's education, school officials reversed the grading system, turning the numerical equivalent of A's into F's (and confusing unwary future biographers).
Einstein did fail his first round of entrance exams -- due to extenuating circumstances. When the young man applied to the Swiss Federal Institute of Technology, he was a 15-year-old dropout who lacked the equivalent of a high school diploma. Moreover, the rigid educational system that he grew up in did not provide him the background in French, chemistry and biology that he needed to pass the institute's exams. He scored so highly on his mathematics and physics tests, however, that the university accepted him anyway, on the condition that he complete his secondary education soon after.