Step 1: Divide the number into separate digits:
1180 => 1 1 8 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 1 = 0
1 to 8 = 7
8 to 0 = 8
0 to 1 = 1
Step 3: Combine the filters to a string:
0 7 8 1 = 0781