Step 1: Divide the number into separate digits:
9469 => 9 4 6 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 4 = 5
4 to 6 = 2
6 to 9 = 3
9 to 9 = 0
Step 3: Combine the filters to a string:
5 2 3 0 = 5230