Sub Macro5()
With Selection.Validation
.Delete
.Add Type:=xlValidateCustom, AlertStyle:=xlValidAlertStop, Operator:= _
xlBetween, Formula1:="=ESTNUM(A1)"
.IgnoreBlank = True
.InCellDropdown = True
.InputTitle = ""
.ErrorTitle = ""
.InputMessage = ""
.ErrorMessage = ""
.ShowInput = True
.ShowError = True
End With
End Sub