Replace your formula with:

=TEXT(A1+1,"0000000000")

HTH
Jason
Atlanta, GA

-----Original Message-----
I am typing in telephone numbers to Excel. An example
is 01253712345. Excel
removes the leading zero, however when I type in '
before the number, the 0
is displayed.
I want to run consecutive numbers, so type in +sum(a1+1)
to give consecutive
numbers. However, the zero again disappears.

How can I apply a custom format to a cell that already
contains a +sum
formula?

Thanks
.