The legend of Einstein being bad in Math once may have originated this way:

Einstein was in school in Germany but graduated in Switserland. Most Germans do not know that the grading scale (6-1) in Switserland is exactly the opposite as in Germany (1-6), with 6 meaning excellence in Switserland and dismal performance in Germany. So my guess is that a German once saw Albert's Swiss grades and made the wrong inference. That legend has been in the world since and will still be offered as an argument against degrees in 50 years.

Wolfgang