Colin Hayes wrote:

My formula in F3 is

=IF(B3="W",(SUM(C3/E3)*D3),C3*-1)

How can I amend this to suppress the DIV/0 error when I put "W" in B3?

I've seen various formulae which suggest they can do this , but can't
see how to merge them into the existing formula.

Add another if that explicitly checks E3=0:

=IF(B3="W",IF(E3<0,(SUM(C3/E3)*D3),""),C3*-1)

Change the "" to whatever you want to happen when you would normally get
div/0 error.

--
That's an ugly monkey.