Sub По_колонке()
    Application.ScreenUpdating = False
    On Error GoTo Err0
    Dim k As Integer
    Dim i As Integer
    Const c As Integer =  5        ' первая строка
    Const d As Integer =  1000   ' последняя строка
    
    Sheets("Лист1").Select
    k =  0 
    For i = c To d
        a0 = Range("A" & LTrim(Str(i))).Value       ' значение ячейки
        If Val(a0) <>  0  Then
            k = k +  1 
        End If
    Next
    MsgBox "прочитал " & LTrim(Str(k)) & " чисел"
    Application.ScreenUpdating = True
    Exit Sub
Err0:
    Application.ScreenUpdating = True
    MsgBox Err.Description & vbCrLf & "на строке   " & Str(i)
End Sub