In Hogwarts Legacy, there are many locked doors inside arches decorated with 10 icons of magical, mythical creatures, and opening these doors requires solving math puzzles that can be a little confusing at first. Several of these puzzle doors are in the Library Annex part of the Hogwarts School of Witchcraft and Wizardry, including one close to the Divination Classroom Floo Flame, which is high above the Central Hall of the Library Annex.
Related: How to complete the Charms Classroom door puzzle in Hogwarts Legacy
How to open the Divination Classroom puzzle door in the Library Annex
The puzzle door isn’t inside the Divination Class itself, but it’s very close to the Divination Classroom Floo Flame, so either fast travel there, or set it as a waypoint and walk there. From the Divination Floo Flame, head northwest, then turn left, then right, and you’ll find the puzzle door surrounded by blackboards and stacks of books.
To unlock the door, you need to roll the symbols in the triangles either side of the door so that the numbers on the points of the triangles add up to the numbers inside the triangles. The symbols around the door correspond to the numbers 0 – 9, reading left to right. So, the top triangle reads 2 + 3 + ? = 9, which means the missing number must be 4, which is represented by the owl icon (at least, it’s supposed to look like an owl). Roll the triangle on the left until it displays an owl.
The bottom triangle reads 0 + 1 + ?? = 4, so the missing number must be 3, which is represented by the hydra icon. So, roll the triangle on the right until it shows a hydra. Now you should be able to open the door and reach the Arithmancy Classroom beyond it. You can also find the Arithmancy Classroom Field Guide page and the Telescope Conjuration exploration collectible beyond this door.
