Arithmancy (class)

"Oh, it's wonderful! It's my favourite subject!"

- Hermione Granger

Arithmancy is an elective subject offered from the third year on at Hogwarts School of Witchcraft and Wizardry. During the 1990s at least, the class was taught by Professor Septima Vector in Classroom 7A, on the Castle's seventh floor. Homework assignments, which included writing essays, required the consultation and/or composition of complex number charts. Little else is known about the class, but the study of Arithmancy has been described as "predicting the future using numbers," with "bit of numerology" as well.

Arithmancy was Hermione Granger's favourite subject at Hogwarts. She once told Harry Potter it was "wonderful" when he remarked that her challenging homework looked "terrible." However, one of her roommates said that, in her opinion, it was difficult, and by far preferred Care of Magical Creatures.

Another subject, Advanced Arithmancy Studies, was taught at Hogwarts, presumably to the most intelligent and brilliant students. It may have been taught by Professor Vector also, and the Advanced Arithmancy Studies classroom was located on the first floor of the Hogwarts Turris Magnus in Hogwarts Castle.

An O.W.L. in the subject was necessary to apply for a Curse Breaker position at Gringotts.

Textbooks

 * Numerology and Grammatica

Known Professors

 * Septima Vector

Known O.W.L.s

 * Barty Crouch Jr.
 * Bill Weasley
 * Bridget Wenlock (presumably)
 * Hermione Granger
 * Percy Weasley
 * Septima Vector
 * Ginger haired Gryffindor student (possibly)

Behind the scenes

 * In Harry Potter and the Order of the Phoenix, Hermione mentions Arithmancy telling Ron that she passed.
 * Hermione also mentions the subject a lot of times in Harry Potter and the Prisoner of Azkaban. She says that she signed up for Arithmancy and constantly refers to it.
 * In the GBC versions of Harry Potter and the Philosopher's Stone and Harry Potter and the Chamber of Secrets, the Arithmancy classroom features a multiplication chart and a blackboard with a simple equation on it.

Appearances

 * Harry Potter and the Philosopher's Stone (video game)
 * Harry Potter and the Chamber of Secrets (video game)
 * Harry Potter and the Prisoner of Azkaban
 * Harry Potter and the Order of the Phoenix
 * Harry Potter and the Order of the Phoenix (video game)

Notes and references
Arithmancie Aritmanzia (classe) Voorspellend Rekenen (schoolvak) Numerologia Нумерология