Step 1: Divide the number into separate digits:
8022 => 8 0 2 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 0 = 8
0 to 2 = 2
2 to 2 = 0
2 to 8 = 6
Step 3: Combine the filters to a string:
8 2 0 6 = 8206