Step 1: Divide the number into separate digits:
90376 => 9 0 3 7 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 0 = 9
0 to 3 = 3
3 to 7 = 4
7 to 6 = 1
6 to 9 = 3
Step 3: Combine the filters to a string:
9 3 4 1 3 = 93413