Step 1: Divide the number into separate digits:
9329 => 9 3 2 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 3 = 6
3 to 2 = 1
2 to 9 = 7
9 to 9 = 0
Step 3: Combine the filters to a string:
6 1 7 0 = 6170