The author credits Hermione Granger with 11 top exam results in the first hardback edition of book six, Harry Potter And The Half-Blood Prince.Link (via Fark)
But in book five – Harry Potter And The Order Of The Phoenix – we are told she takes TEN examinations
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.