Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Count > 1 Then Exit Sub
If Not Intersect(Target, Range("A1:A3")) Is Nothing Then
ro = Target.Row: co = Target.Column
b = Val(Cells(ro, co))
b = b / 25.4
Cells(ro, co + 2) = b
MsgBox "Les cellules sont converties en impériales."
End If
End Sub