To tell you why, put some text (any text) in B2 and a number (any number) in
C2, and see what =B2C2 gives you.
You can, of course, include a condition such as ISNUMBER(A10) in your CF
criteria.

Alternatively, if instead of writing text to A10 you merely write an error
indication such as NA() [or #N/A] or #DIV/0!, then your condition when you
compare with a number in A1 or A2 will return FALSE.
--
David Biddulph

"Brian" wrote in message
...
I have a question about conditional formating. The way I understand CF is
that I can have 3 conditions and a "default." I have set mine up like
this:

A1 80%
A2 60%
A3 0%

Condition 1
formula is =A10=$A$1
Shades the cell Green

Condition 2
formula is =A10=$A$2
Shades the cell Yellow

Condition 3
formula is =A10<$A$2

This works fine when the formula in A10 returns a number (most cases), but
I
use the ISERROR() function to catch some Div/0 issues and replace them
with a
text message (Usually "N/A"). In these situations, excel still formats
the
cell Green, instead of the default of no shade, and I don't know why.
Thanks
for any help.