Step 1: Divide the number into separate digits:
1077 => 1 0 7 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 0 = 1
0 to 7 = 7
7 to 7 = 0
7 to 1 = 6
Step 3: Combine the filters to a string:
1 7 0 6 = 1706