Return One Number if Cells Contain Same Value

Hey All,

I'm looking for a formula that will help me calculate the percentage change between "pre" and "post" numbers. The catch is that there could be multiple columns for "pre" numbers, but they will all the same if there are numbers. I have included an excel sheet for reference that better explains my question.

Basically IF "pre" columns has a number THEN use just the single number in the calc.

Thank you for any help provide.

That is perfect.

Thank you very much.