100 doors level 48
But it's right if you look at another code on the ground, because it's not decimal equation but it's date equation, on above code 815 mean august 15. and 904 means September 4. So you can understand the equation now.
Then The answer for
100 doors 48
fill square with number 23and fill triangle with number 10
Now dates equation game is correct
After answering 100 doors level 48 now you can go to solution door49