Step 1: Divide the number into separate digits:
0848 => 0 8 4 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 8 = 8
8 to 4 = 4
4 to 8 = 4
8 to 0 = 8
Step 3: Combine the filters to a string:
8 4 4 8 = 8448