Step 1: Divide the number into separate digits:
90838 => 9 0 8 3 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 0 = 9
0 to 8 = 8
8 to 3 = 5
3 to 8 = 5
8 to 9 = 1
Step 3: Combine the filters to a string:
9 8 5 5 1 = 98551