Once you've been sorted into your house in Hogwarts Legacy and are free to roam around the campus, you might stumble upon some mysterious doors with various symbols surrounding it and strange numbers on the front. Naturally, you will be drawn to open it, only to find it locked. These aren't doors you can open with your normal lockpicking spells, no matter how high you level them up. Instead, you will need to use your wits to overcome this obstacle. That, or simply follow this guide to open the Arithmancy doors in Hogwarts Legacy.
How to open Arithmancy doors
Arithmancy doors are essentially math problems in disguise. You're supposed to determine which animal around the frame corresponds to what number and then determine what numbers fit in the ? spots on the two triangles on the door's face. Put simply, to solve these puzzles you need to make the sum of the values of the three numbers and animals around the triangle equal to the big number inside the triangle. If you aren't sure how to do that, or the value of the arithmancy door animals, follow these steps:
Step 1: Interact with the door to see the interior triangles.
Step 2: Add the two known numbers of each triangle together. If you see an animal and not a number, check this cipher to convert it into a number.
Step 3: Subtract the number inside the triangle from the sum you just got.
Step 4: Take those two new numbers and find which animal they correspond to.
Step 5: Locate the ? and ?? symbols on the walls nearby.
Step 6: Interact with each of them until they show the correct animal.
Step 7: Once both have the correct animal showing, the door will open and you can claim the loot inside.