Step 1: Divide the number into separate digits:
96669 => 9 6 6 6 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 6 = 3
6 to 6 = 0
6 to 6 = 0
6 to 9 = 3
9 to 9 = 0
Step 3: Combine the filters to a string:
3 0 0 3 0 = 30030