Step 1: Divide the number into separate digits:
0886 => 0 8 8 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 8 = 8
8 to 8 = 0
8 to 6 = 2
6 to 0 = 6
Step 3: Combine the filters to a string:
8 0 2 6 = 8026