"That is an urban legend. Einstein was not bad at math. You only need to study the general theory of relativity to know that."
It's not an urban legend, actually. He was lousy at math in the primary grades. He got over it. He was still a social klutz, though, and needed help in choosing his clothing. He had as much fashion sense as I do, in fact: little to none. His parietal lobes were also about 15% larger than normal, according to the autopsy report... Had better things to do with that capacity, after all.
That is sort of a mischaracterization. He performed poorly in math because he couldn't stand the rigid German school system. It is not so much that he got over it than that he was eventually able to use his mind in a less restricted sense. It wasn't through a great deal of study that he became the greatest physicist of the last century, it was because of his unique reasoning ability.