OK, it'* up to you to figure this out. Follow the directions. Go to the
site shown below. This will boggle your mind...Take your time and follow
the instructions. After reading each window click on the boy in the
lower right corner. You will be amazed....and no, I don't know how it'*
The difference between any three or four digits and their lesser anagram result in unique combinations of numbers. For any pair or trio of numbers in the answer, that group will only appear with one or two other numbers, usually nine or zero if there are two possibilites. That is why it tells you not to pick zero. If you pick a zero, it will predict nine.
I challenge you to find two differences that have the same trio of numbers in any order, and the fourth digits be different, but neither zero.
Did I explain that well enough? Sometimes I have trouble explaining things.