Question : Using Cell Value in a Formula

I would like to be able to use a cell value as part of a formula.  Something that seems like it should be simple.  For instance in a cell (say A1) I have the number 500.  I would like another cell to use that number to reference a cell.  So the formula would produce something like:

=A500

So how can I change that formula (or any formula) to use the value of A1 instead of manually putting the 500 in it?

Answer : Using Cell Value in a Formula

Try this:
=CONCATENATE([MyWorksheetName.XLS]Sheet1!$A$1,A1)