Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
Range("B2").FormulaLocal = "=SOMME(janvier:février!A1)"
Worksheets.Add Before:=Sheets(Sheets.Count)
ActiveSheet.Select
If Sheets.Count > 13 Then
ActiveSheet.Name = Format(30 * (Sheets.Count - 1), "mmmm yy")
Else
ActiveSheet.Name = Format(30 * (Sheets.Count - 1), "mmmm")
End If
End Sub