I'd do something like:
Sub ar2()
Dim i As Long, a As Long, b As Long
Dim colno As Long, lr as Integer
For colno = 3 To 7
a = 0
b = 0
lr = Cells(Rows.Count, colno).End(xlUp).Row
For i = 2 To lr
a = a + Cells(i, colno).Value
If Cells(i, colno).Value <> "" Then b =...