My solution to that is to add in place holder sheets. Add a newe sheet called
'Start' at the front fo the book an done called 'End' at the end of the book.
Now make your formula
=sum(Start:End!A1)
Now hide the Start and End sheets. Any sheets that are added will be added
between start and end so the total will include all sheets.
--
HTH...

Jim Thomlinson


"Damian" wrote:

Do sum up cell A1 of each worksheet from 1 to 6 I would use this function:
=SUM(Sheet1:Sheet6!A1)

BUT what if I don't know how many worksheets I will be having. Maybe 50 or
100.
How can I write a function to sum up all the worksheets?

When I use this formula:
=SUM('*'!A1) It works if you know how many you will have, but not if you
keep adding more. Because that function above turns into this
=SUM(Sheet1:Sheet6!A1) - depending how many worsheets you have, so if you
would add a 7th, it would not count that.

Anyone have any suggestions?

Thank you