> 
> Does anyone know if there is a way to use the SUM function across
> worksheets? For example:
> 
> =sum(sheet1!a1:sheet7!a1)
> 
> All I get ia a #VALUE error message, but I can add them up using the +
> sign, but this is rather tedious. Any suggestions gratefully received!

Formula must be like:

=sum(sheet1:sheet7!a:b)

Just select several sheets together (with shift key) before mouse
clicking on source area ...

There is Excel 7