Option Explicit
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim i As Integer
If Not Intersect(Range("F:F"), Target) Is Nothing And Target.Count = 1 Then
For i = 1 To Range("F" & Rows.Count).End(xlUp).Row
If Cells(i, 6) <> "" And Cells(i, 6).Font.Strikethrough = True Then
Cells(i, 8).FormulaLocal = "=D" & i
ElseIf Cells(i, 6) <> "" And Cells(i, 6).Font.Strikethrough = False Then
Cells(i, 8).FormulaLocal = "=D" & i & "+ F" & i
End If
Next i
End If
Exit Sub
End Sub