Metal Door in Cellar | Nancy Drew: Ghost of Thornton Hall

Find a way to unlock the door in the tunnels:
At the cellar, enter the tunnel right of Harper and left of the generator.
Open the panel of the metal door.

Amateur:    Each of the 4 edges is equal to the plaque's first and seventh numbers side by side

Using the clue on Franklin's memorial, arrange the numbers to add up to 18 on all sides.

Master:    The top and bottom edges are equal to the day of Franklin's death, the day of his dedication equal to either side. Franklin died on the 25th and the dedication was on the 15th.