Value to change when opening a new file.

Occasional Visitor

When opening a new excel document, in the same file, I want the numbers to change to the next sequence. If its a work order number, I want the next time it is opened to go to the next consecutive number. I need a cell or sheet tab to say WO#500000, then the next time a new file is opened, I need that number to change to WO#500001.


Sorry for any confusion. I may have posted this once. but I cant find the question any where.