Step 1: Divide the number into separate digits:
76708 => 7 6 7 0 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 6 = 1
6 to 7 = 1
7 to 0 = 7
0 to 8 = 8
8 to 7 = 1
Step 3: Combine the filters to a string:
1 1 7 8 1 = 11781