"Did yeh never wonder where yer parents learned it all?”
“All what?” asked Harry.
“ALL WHAT?” Hagrid thundered. “Now wait jus’ one second!” He had leapt to his feet. In his anger he seemed to fill the whole hut. The Dursleys were cowering against the wall. “Do you mean ter tell me,” he growled at the Dursleys, “that this boy — this boy! — knows nothin’ abou’ — about ANYTHING?”
Harry thought this was going a bit far. He had been to school, after all, and his marks weren’t bad.“I know some things,” he said. “I can, you know, do math and stuff.”