Step 1: Divide the number into separate digits:
0895 => 0 8 9 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 8 = 8
8 to 9 = 1
9 to 5 = 4
5 to 0 = 5
Step 3: Combine the filters to a string:
8 1 4 5 = 8145