Excel Recursive function or not..! Pl help

I dont know gold and Im still struggling to understand what you are trying to do?

1+9 = 9?????

I know Im getting old, and things change in schools, but I didnt think they would change basic math?

ok, that is fair.So..

I am starting at hole no 1. If I play 9 holes, I end at hole number 9. If I play 18-hole round, I end at hole 18.
(so we are counting the hole that we start on..therefore 1+9=9...!)

If I play a 9-hole scramble, I can start only on the hole that I am assigned. Therefore I could start at hole 5, I end at hole 13. If I start at hole 13, I end at hole 3.
If I play a 18-hole scramble,I could start at hole 5, I end at hole 4. If I start at hole 13, I end at hole 12.

For those that are not golf-savvy
Front nine- 1 through 9 (holes)
Back nine - 10 through 18 (9 holes)
..and only in a tournament, start any hole and end after playing 9 or 18, hole 1 following hole 18.

I need to set up my excel so that I enter a starting hole and provide 2 scenarios (Playing 9 or 18, format of play - regular or scramble) and I should automagically be provided the finishing hole, completing the four columns- Starting hole,9/18, Format, Finish hole. Phew...a formula for the Finish Hole calculation is what I need to get.Savvy?