I'm using the following macro to format phone numbers from "1234567890" to
"123-456-7890". While this works fine on single cells when I try it on a list
it deletes the numbers and inserts the dashes "--".
What is wrong with this? Thanks.

Sub InsertDashes()
Set r = Selection
v = r.Text
v = Left(v, 3) & "-" & Mid(v, 4, 3) & "-" & Right(v, 4)
r.Value = v
End Sub