excel - Add Total Row For Columns D - M -

i have been using syntax add total row column d - need add total row d - m. instead of writing code multiple times , changing column name there quick re-usable function add total row bottom of columns d - m?

with activesheet if application.worksheetfunction.counta(.cells) <> 0     lastrow = .cells.find(what:="*", _                   after:=.range("d1"), _                   lookat:=xlpart, _                   lookin:=xlformulas, _                   searchorder:=xlbyrows, _                   searchdirection:=xlprevious, _                   matchcase:=false).row else     lastrow = 1 end if end range("d" & lastrow +1).formular1c1 = "=sum(r[-" & lastrow & "]c:r[-1]c)" 

this has same effect highlighting range , hitting ctrl+right arrow

range("d" & lastrow + 1 & ":m" & lastrow + 1).fillright