Option Explicit
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Not Intersect(Target, Range("e2:e6")) Is Nothing Then
If Application.WorksheetFunction.CountA(Range("e2:e6")) = [a2] Then Exit Sub
If Application.WorksheetFunction.CountA(Range("e2:e6")) < [a2] Then
MsgBox [a2] - Application.WorksheetFunction.CountA(Range("e2:e6")) & " quantité(s) en moins !"
Else
MsgBox Application.WorksheetFunction.CountA(Range("e2:e6")) - [a2] & " quantité(s) en trop !"
End If
End If
End Sub