Step 1: Divide the number into separate digits:
07774 => 0 7 7 7 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 7 = 7
7 to 7 = 0
7 to 7 = 0
7 to 4 = 3
4 to 0 = 4
Step 3: Combine the filters to a string:
7 0 0 3 4 = 70034