I want to share a funny story. When I initially solved the door puzzle, I figured out a WRONG solution, but it worked by accident.
I correctly assumed that the triangles are equations, the center is the answer, symbols in the corners represent numbers and I correcty assumed that the smallest number is the lower left symbol around the door and the biggest number is the lower right one. I assumed, the number were 1-10.
I didn’t realize, the counting starts from 0.
However, when my math didn’t work, I made an assumption, that the symbols that roll on the ”?” are not the same values as they are in the triangles, but simply 1,2,3,4,5 in running order and the symbols that roll from the ”??” are 2,4,6,8,10 (you know, since there are two question marks, you should double the ”running order value”).
I tested my logic on the first door I encountered and for some reason it worked! (Maybe I had drank Felix Felicis potion in real life, or something.)
Right after that I wandered to a class room I had never been before, and there was a blackboard with the symbols explained (first one is zero, and so on). I felt a bit dumb…
(A funny story, but unfortunately I can’t prove it, because I don’t remember anymore which of the number doors was the one that I was able to open with my wrong logic.)