Step 1: Divide the number into separate digits:
0389 => 0 3 8 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 3 = 3
3 to 8 = 5
8 to 9 = 1
9 to 0 = 9
Step 3: Combine the filters to a string:
3 5 1 9 = 3519