Step 1: Divide the number into separate digits:
8761 => 8 7 6 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 7 = 1
7 to 6 = 1
6 to 1 = 5
1 to 8 = 7
Step 3: Combine the filters to a string:
1 1 5 7 = 1157