If you want the cell blank when equal to zero, it's not necessary to add a
space, try this instead:
=IF(W3-V3=0,"",W3-V3)
and set your conditional format to:
=$X2<""
or
=$X2<" "
if you prefer your original formula.
"" is called a zero length string - a string that contains no characters.

"Wanna Learn" wrote:

Hello I have the following formula in a cell =IF(W3-V3=0," ",W3-V3). I'm
trying to conditional format all cells that have an answer and I used the
following formula in the conditional format window =$X2<0 . And it
highlight the cell . How do I correct this I thinki t has to do with the if
formula and " " but i dont know how to correct it thanks