Where do you expect them to "combine"?

Perhaps one way:

IF(ISERROR(G4+D4),ROUNDUP(G4,1),IF(OR(G4="",D4="", G4<=0),"",
ROUNDUP(G4,1)+D4))

but I don't understand what you're trying to trap with ISERROR() - will
G4 or D4 contain an error? If G4 contains either an error or text,
ROUNDUP(G4,1) will pass on the error...

In article ,
Dennis1188 wrote:

I need help joining this...

=IF(ISERROR(G4+D4),G4,IF(OR(G4="",D4=""),"",IF(OR( G4<=0),"",G4+D4)))

with this...

ROUNDUP(G4,1)