Step 1: Divide the number into separate digits:
9472 => 9 4 7 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 4 = 5
4 to 7 = 3
7 to 2 = 5
2 to 9 = 7
Step 3: Combine the filters to a string:
5 3 5 7 = 5357