SALE!! $1 until 18th noon-ish Pacific Time. [internet (cellular or wifi) needed.] So you want to learn math among other things. Why not get a interactive multimedia experience?
Before buying, please see NOTE at the end of this description.
KNOW IT is anything but a textbook approach to brainy topics (like math and physics). The KNOW IT series allows readers to enjoy a rich experience. A KNOW IT lesson may include not only text but anything that uses iOS web technologies: Javascript, HTML, online lectures, online audio, and online pictures. We have already implemented "speech buttons" that will read the lesson in the main window. We expect to expand further to more iOS technologies (such as using the camera and microphone) but not as of now.
NOTE: Were just getting started and have a few "technical demos" available inside the App. I expect to add at least 10-20 minutes of audio every day (on average).