Step 1: Divide the number into separate digits:
7622 => 7 6 2 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 6 = 1
6 to 2 = 4
2 to 2 = 0
2 to 7 = 5
Step 3: Combine the filters to a string:
1 4 0 5 = 1405