Step 1: Divide the number into separate digits:
44402 => 4 4 4 0 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 4 = 0
4 to 4 = 0
4 to 0 = 4
0 to 2 = 2
2 to 4 = 2
Step 3: Combine the filters to a string:
0 0 4 2 2 = 00422