Step 1: Divide the number into separate digits:
5297 => 5 2 9 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 2 = 3
2 to 9 = 7
9 to 7 = 2
7 to 5 = 2
Step 3: Combine the filters to a string:
3 7 2 2 = 3722