One way:

SUM() will ignore text:

=-SUM(-I4,Q4)

In article ,
Shakeel wrote:

Hello all
My problem is I have simple formula in column B, "=I4-Q4", but I got #VALUE!
error, Column I have value enter by self, but Column Q have Vlookup formula
i.e. "=IF(O4="","",VLOOKUP(O4,Stock,29,FALSE))"
Simple I need result in Column B "I4-Q4" if Q4 is blank then I4 value in
Column B

Thanks