Step 1: Divide the number into separate digits:
07180 => 0 7 1 8 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 7 = 7
7 to 1 = 6
1 to 8 = 7
8 to 0 = 8
0 to 0 = 0
Step 3: Combine the filters to a string:
7 6 7 8 0 = 76780