With Sheets("nomfeuille")
.Range("C" & Tot.Row + 11).Value = Application.Sum(.Range("C" & Tot.Row + 7) & ":" & .Range("C" & Tot.Row + 10))
End With
.Range("C" & Tot.Row + 11).FormulaR1C1 = "=SUM(R[-4]C:R[-1]C)"
With .Range("C" & Tot.Row + 11)
.FormulaR1C1 = "=SUM(R[-4]C:R[-1]C)"
.Value = .Value
End With