Is it true that Albert Einstein failed math as a student?

No, Albert Einstein never failed math as a student. Einstein was an accomplished mathematician, even at a young age. This is true in spite of stories that claim he struggled in math during his younger years.

Einstein himself stated that before he turned 15 years old he had already mastered differential and integral calculus. His sister recalled that when Einstein was 12 that he was able to solve complicated math problems and that he jumped ahead in his studies to learn geometry and algebra on his own. Einstein studied math textbooks over the summer so he could learn proofs and create his own.