Sub test()
Dim T As Variant
Dim i&
With Sheets("increment")
T = .Range(.Cells(1, 1), .Cells(.Rows.Count, 1).End(3)(1, 3))
For i = LBound(T, 1) To UBound(T, 1)
T(i, 3) = T(i, 1) + T(i, 2)
Next i
.Cells(1, 1).Resize(UBound(T, 1), UBound(T, 2)).FormulaLocal = T
End With
End Sub