I tried this but I get...
1,2,3 instead of 1,1a,1b,1c etc...
Dim strWhere As String
Dim intChar As String
intChar = Asc(Nz(DMax("NumberID", "tblTest", "NumberID = '" & Me.Text3 & "'"), "@"))
Me.TxtNumber = Me.TxtNumber & Chr(intChar + 1)
Thanks
DSTR3