I have a spreadsheet in which there are two columns that I want to perform a check on. The spreadsheet is an input page where there is a product column and a column for the number of hours the product stayed in the tank.

The input sheet is just for 24 hour analysis, therefore for each product the number of hours has to sum to 24.

For example,

Product---------------------Hours

LS60G-----------------------21

HS100G---------------------24

LS60G------------------------3

The above example is correct, each product's hours sum to 24.

I would like a way to check that each product's hours sum to 24. If they do not equal 24, I will let my macro display a msgbox prompting the user to go back and correct the mistake. So, I guess somewhere there needs to be the sum of the hours of each product (I'm not sure how to go about it)

How could I accomplish this (without a macro)?

I have attached an example of my problem below. The cells in the product column have pull-down menus which display every available product.

Please Help!

Thanks!