Need help combining three formulas for both Excel and VBA for automation.

Is there a way to combine the formulas below into one?

=SUMIFS(NT_TOT,NT_ID,_ID)

=COUNTIFS(ID2,ID,CODE2,306,DT2,">.1")
+COUNTIFS(ID2,ID,CODE2,307,DT2,">.1")


=IF(ISERROR($G15/$H15),(G15),($G15/$H15))


Right now it is just a formula in worksheet, however, I will be doing this report on a long-term basis and I will also need to automate it in VBA, so both formulas (if you know them) would be appreciated. I am very new to complex formulas in Excel and VBA code.

1) =SUMIFS(NT_TOT,NT_ID,_ID) - totals items from one set of data

2) =COUNTIFS(ID2,ID,CODE2,306,DT2,">.1")+COUNTIFS(ID2,ID,CODE2,307,DT2,">.1") - totals items from second set of data

3) =IF(ISERROR($G15/$H15),(G15),($G15/$H15)) = sum of #1 divided by the sum of #2

I'd like it if the cell only showed the result of the third formula after calculating the two.