I copied a sumif formula accorss a worksheet, and then tried to make some
changes to the formula in one of the cells. When I made the change, the
formula discontinued working and became text . For example, I typed the
following in the cell:

=2+2

The result was =2+2, not 4 as it should have been. I know the cell is
formatted as text. Why did this happen? What prevents a formula from
changing automatically to text?

Many thanks..

--
Tom