There is another story that is related to Karna‘s childhood. Karna, was spurned by every known teacher for being not belonging to the warrior caste (Kshatriya). Atlast, he approached the sage Parasurama, to accept him as a student. Now Parasurama, had been a sworn enemy of the Kshatriyas (warrior caste). But he accepted only Brahmin (priestly class) students. So Karna lied to him that he was a Brahmin boy.
And he began learning weaponry from Parsurama.