Not sure my logic is correct with this, but I thought i would give it a go. I have used an IF OR statement and then on the true variable embedded an IF AND statement. Within the attached spreadsheet, cells D13 and D14 I check 1st for validity - in the example I have given, the values fall within the true range so should then calculate the exponential - this is not happening. In cell G16 I have checked what I believe the output should be for the below. Within the worksheet I have embedded an image of the calculations I am trying to automate. i decided to start with those circled in red with 1 and then check 2....
Thanks in advance, Paul