Step 1: Divide the number into separate digits:
09982 => 0 9 9 8 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 9 = 9
9 to 9 = 0
9 to 8 = 1
8 to 2 = 6
2 to 0 = 2
Step 3: Combine the filters to a string:
9 0 1 6 2 = 90162