If negative number than 1+2, if posative number than 1

[Cheryl]

how would you enter the formula for:
if A4 is a negative number than add A4+A5, but if it is not a negative
number than just A5?

 

[Elkar]

Try this:

=MIN(A4,0)+A5

The MIN function returns the lower of the 2 values (A4 or 0). This is then
added to A5.

And here's another option, using an IF statement:

=IF(A4<0,A4+A5,A5)

HTH,
Elkar