Function Calculator(ByRef RangeFrom As Range, ByRef RangeTo As Range)
Dim TabList As Variant
Dim i As Integer
Dim Counter As Double
Dim Container As Variant, MyItem As Variant
Application.Volatile
TabList = Range(RangeFrom, RangeTo)
Dim ColList As New Collection
On Error Resume Next
For i = 1 To UBound(TabList, 1)
ColList.Add TabList(i, 1) & "#" & TabList(i, 2), TabList(i, 1) & "#" & TabList(i, 2)
Next i
On Error GoTo 0
For Each MyItem In ColList
Container = Split(MyItem, "#")
Counter = Counter + Container(1)
Next MyItem
Calculator = Counter
End Function