avoid Descending Sort putting error cells uppermost in collumn

[Romileyrunner1]

Hi, have collumns with numerical results but also error cells which appear
blank due to the formula:
=IF(ISERROR((GD17-FE17)/2),"",(GD17-FE17)/2)
being applied.

When I sort on `desending order` I want the highest numerical results at top
of collumns and the error (BLANK) cells at the bottom.

Any suggestions Guys?
Thanks.

 

[Gary''s Student]

=IF(ISERROR((GD17-FE17)/2),-999999,(GD17-FE17)/2)
or any other very large negative value

 

[Romileyrunner1]

Great works fine: Thanks Gary`s Student!
I`m using just -999 which is small enough.
But how do I use conditional formatting to `white-out` the text for those
cells
I`ve tried <900 and =-999 as conditions, But they don`t seem to work?
Any ideas about this?
Thanks.

 

[Romileyrunner1]

Hey, no need to reply: just found out what I was doing wrong>
I already had another condition running <3 (to turn pink) and this was
obviously conflicting with the <900 or indeed =-999 commands .
Perhaps I need to take a break!!!!!
Thanks anyhow.