Draw and Tell HD is a drawing (and recording!) app created by Duck Duck Moose (the same company who created Chatterpix Kids). It's free today for the first time!
Students can choose from a variety of backgrounds, including notebook paper, graph paper, primary handwriting paper, patterns or even a picture from the camera roll.
Once students have created their drawing, they can tap the microphone icon and record themselves explaining their picture. This would be great for explaining math reasoning or practicing reading vocabulary or spelling words.
The creations automatically save within the app and can be saved to the camera roll. You can even combine multiple pictures/recordings into a single movie to save to the camera roll. This would be an easy way to create a "book" (slideshow) about math fact families or word families.
One tip: While the music might be a little annoying, you'll probably want students to have their sound turned on the first time they use the app because it does give instructions about how to use it.