Online whiteboards that let students communicate in realtime either by voice or text can be powerful tools to create a mathematics tutorial, create a diagram, or to brainstorm ideas for a project. The following three whiteboard tools can all be used by students for free.

NoteBookCast is a free whiteboard tool that will work in the web browser on a laptop, iPad, Android tablet, and Windows tablet. NoteBookCast is a collaborative whiteboard tool. You can invite others to join your whiteboard by entering the code assigned to your whiteboard. You can chat while drawing on NoteBookCast whiteboards. In the video embedded below I demonstrate how to use NoteBookCast.

Web Whiteboard makes it easy to include a whiteboard in your Google+ Hangout. In the video embedded below I demonstrate how easy it is to use Web Whiteboard in a Google+ Hangout.

Stoodle is a free collaborative whiteboard tool hosted by the CK12 Foundation. You can use text chat while sharing your whiteboard. Registration is not required in order to use Stoodle. In the video embedded below I demonstrate the features of Stoodle.