/ http://www.slideshare.net/images/logo.gif / ºÝºÝߣShare feed for ºÝºÝߣshows by User: XuanDoCao https://cdn.slidesharecdn.com/profile-photo-XuanDoCao-48x48.jpg?cb=1523012688 -------------------------------------------- 6! = 720 " Sáu giai thừa" It`s my name. Trùng hợp thôi.