Step 1: Divide the number into separate digits:
97994 => 9 7 9 9 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 7 = 2
7 to 9 = 2
9 to 9 = 0
9 to 4 = 5
4 to 9 = 5
Step 3: Combine the filters to a string:
2 2 0 5 5 = 22055