Step 1: Divide the number into separate digits:
9884 => 9 8 8 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 8 = 1
8 to 8 = 0
8 to 4 = 4
4 to 9 = 5
Step 3: Combine the filters to a string:
1 0 4 5 = 1045