Arithmancy is an elective subject offered at Hogwarts from third year. Arithmancy involves the study of predicting the future with numerology and numbers.
 While in Class
The Arithmancy classroom is located on the seventh floor of the castle in Classroom 7A. The class work and assignments given usually involve complex number charts and writing essays.
Hermione Granger took the subject while she was at Hogwarts which was her favorite subject.
 Professors of Arithmancy
Professor Septima Vector