Formula error

I am having trouble with an formula. I want to add cells from many sheets. The formula I have been trying is.... =Sum('First'!E6:'Last'!E6). I want it so when I add worksheets between my named first and last sheets I don't have to update the formula on the totals page.

Excel will automatically do this if you insert worksheet between the sheets that you have selected for the formula.

I need the formula so I don't have to list each individual worksheet. I know if I have the range from first to last that any inserted sheets would automatically be added in. I can't get the formula for the range of all the worksheets.

Here´s an example:

=SUM(Sheet1:Sheet3!A1)
Sheet1!A1: =5
Sheet2!A1: =5
Test99!A1: =5
Sheet3!A1: =5
The sum will be =20 since XL will sum all A1 that are Between Sheet1 and Sheet3.

Ola Sandstrom

I used it and that is want I have been looking for. A thousand thanks!!

Thanks for the feedback.
Ola