RV Log

[trukdoc]

Having a new RV that only has the History I have put on it, I would like to log my travels and keep track of the statistics.
There are several paper version that one must manually add the mileage and nights spent. I am going to travel with my laptop I figure there must be a better way.
I have been working on an Excell workbook to do this. I have the layout down good. I am not good with the formulas to subtract start mileage with end mileage to get miles traveled. The program just wants to add. How do I get it to subtract C (Start miles) from D (End miles) to = E (Total miles).

Or is there a program out there already configured and all I must do is download and start useing.
I like what I have started if someone out there can show me where I am going wrong with the formulas.
The other point to useing a Excell workbook is that a PDA could be used and then synchronized to the laptop. Sounds complicated but really is not.
When I get it done I will be happy to share it with anyone that is interested. It shows miles and nights, and notes for our travels. As I get more advanced I can link this to photos as well.(I think)
Rick