Jeff,

Here's how it would look for summing A1 in Sheet1 through Sheet3:

=SUM(Sheet1:Sheet3!A1)

From 2003 Help here's some instructions:
1.. Click the cell where you want to enter the function.
2.. Type = (equal sign), enter the name of the function, and then type an
opening parenthesis.
3.. Click the tab for the first worksheet to be referenced.
4.. Hold down SHIFT and click the tab for the last worksheet to be
referenced.
5.. Select the cell or range of cells to be referenced.
6.. Complete the formula, and press ENTER.
hth,

Doug Glancy

"Jeff Klein" wrote in message
...
I have approx 150 sheets named with my customers name. I want to create a
cell that shows the sum of C12 in each sheet. Each of my clients has a
number in C12 that shows the "Hours Required". I am trying to obtain a
total of all hours for all clients.

='Doe, John'!C12+'Smith, Jane'!C12 Works fine for a few sheets but what
if
I have 150 sheets? What is the formula?
I have also tried =SUM('Doe, John'!C12:'Smith, Jane'!C12) This gives me
"$VALUE!"