One of the best self-directed learning tools on the App Store is Khan Academy, which provides more than 3,500 educational video microlectures on various educational topics from mathematics and humanities to economics. Khan Academy is a not-for-profit dedicated to providing free world-class education for anyone, anywhere. The app offers an extensive spread of mathematical tutorial videos viewable on the iPhone, but the iPad version really shines. iPad users can track their progress, download videos for offline viewing and even display subtitles to follow along with the lecture.
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