One cell takes multiple inputs

I was wondering if there is a simple way to make one cell takes multiple inputs, essentially turning a cell into a placeholder.

Example:

Sheet1!A2=Sheet1!A3+5

Sheet1!A3 will take arbitrary value from Sheet2!A3 or Sheet3!A3, and return the answer to Sheet2!A4 and Sheet3!A4, respectively.

If Sheet2!A3=2, then Sheet2!A4=Sheet1!A2=7
If Sheet3!A3=4, then Sheet3!A4=Sheet1!A2=9

Thank You.

csw

Hi, thanks for the reply. I apologize for the "who knows what you're talking about". I'm really bad at this stuff. But I hate to dissapoint you that I'm not an American, so I don't really get the Yogi Berra joke. Let me see if I can redeem myself so that all American and non-American can understand what I'm trying to do.

Bare with me. What I'm trying to do is, I would like to set up Sheet1 to be a "subroutine" or "function", if you will. Sheet1!A3 will be the argument (a placeholder), and Sheet1!A2 will be the equation that gives me an answer that I can return to other sheets. The problem is, the way I understand it, Sheet1!A3 can only take one value referenced from other Sheets, hence Sheet1!A2 can only return one answer, unless I create tons of duplicate equations. If the equation is A+B, then your advice would be a great solution. But Sheet1 that I have will involve reading table data and curve fit solution. So it's not just a simple equation. I try to avoid custom function or vba cause I think someone might know a way to do it without doing it the hard way.

The more I explain with my english, the more whew...now i have done it again.
Thanks!

Hi, thank you for your quick response. I have four 4x10 tables where 3 coefficients are interpolated from. My list selection will determine which set-of-3 coefficients to use. These coefficients along with other calculations will then be used to solved for an answer (A). Answer (A) can be solved without much effort. However, if I need to use answer (A) derived from other input parameters, then I will either have to give up the initial inputs, or create duplicate but similar procedure. I used vlookup, index, match, etc. to lookup the table values, and I can essentially create a duplicate of the procedure. But, it's Cumbersome. My goal is to try to keep the sheet as lean as possible so it's easy to track in the future. But I guess the only way to do it is through VB, otherwise I'm afraid most programming language would be put out of business.

All I know about Yogi Berra is that he was a great American baseball player.
Thank you very much for your advice. This is a great place to look for solution, I might just stumble upon it someday.