Step 1: Divide the number into separate digits:
0526 => 0 5 2 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 5 = 5
5 to 2 = 3
2 to 6 = 4
6 to 0 = 6
Step 3: Combine the filters to a string:
5 3 4 6 = 5346