Many learning difficulty students don't enjoy writing with pen or pencil in exercise books or on paper, so I thought I had made a major breakthrough when I introduced the small whiteboard to my students for practising new or difficult words. The reluctance dissappeared and they loved the opportunity to play with words, making large or decorated letters and it was so easy to rub out mistakes. Now the little white boards are hardly used as the ipad apps have taken over.
Whiteboard X2 by iEducation Apps, and Chalkboard + Neon by Brian Nelson are the same except for the background colour of the screen. They are quick and simple to use, with options for thickness of line and colour of writing. There are two ways to erase. The children like to use the eraser pen, but this is slow unless it is set to a very thick erasing line. The quick way is to press the eraser button which removes everything on the screen.
There are other more sophisicated drawing apps such as Colorbox by Batsu, that can be used for writing words or sentences, but I find that the multiple choices can distract the student from the task in hand. They are useful when something new is needed to spark an interest in writing a difficult word.