Step 1: Divide the number into separate digits:
9223 => 9 2 2 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 2 = 7
2 to 2 = 0
2 to 3 = 1
3 to 9 = 6
Step 3: Combine the filters to a string:
7 0 1 6 = 7016