Numbers are symbolic in the series, especially 2, 3, 4, and 7. For example, the trio of Harry, Ron, and Hermione suggest the power of three and the spiritual trinity. Harry fatally wounds the basilisk on its third strike, and Hagrid knocks on the front door of Hogwarts three times. Students attend Hogwarts for seven years and there are seven players on each Quidditch team. Sirius is also imprisoned on the seventh floor of Hogwarts.
