Step 1: Divide the number into separate digits:
5260 => 5 2 6 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 2 = 3
2 to 6 = 4
6 to 0 = 6
0 to 5 = 5
Step 3: Combine the filters to a string:
3 4 6 5 = 3465