Step 1: Divide the number into separate digits:
89092 => 8 9 0 9 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 9 = 1
9 to 0 = 9
0 to 9 = 9
9 to 2 = 7
2 to 8 = 6
Step 3: Combine the filters to a string:
1 9 9 7 6 = 19976