how to add the same cell value in a formula automatically from all worksheets?

I am working on a document that contains individual financial information sheets. All the worksheets are the same layout. I will be adding 100+ of these in my excel document. What I need to do is to create a final worksheet that will bring together all totals together in one place. Is there any way that I can create a formula that will automatically add any new worksheet within the document to that formula? (eg. I need to add all the B40 cells of all the worksheets in one formula in a final sheet, how do I do that other than adding each one everytime I make a new worksheet, is there any way for the formula to say: Any B40 of all created worksheets will be added in this formula).

Sorry I am trying to make myself as clear as possible.