The stunning success of Khan Academy, an online learning experiment that has now delivered more than 80-million free lessons worldwide, is well documented at this point. But to listen to MIT and Harvard whiz kid Salman Khan describe his journey is to appreciate the extent to which he has only scratched the surface. For those who are not convinced that digital learning will play a significant role in modern education, Khan shows us four math classrooms in Los Altos, California, public schools that he has flipped upside down.

In those classrooms, teaching is first introduced at home. As homework, students sign in to the online collection of 2,600 videos and interactive software. They proceed at their own pace and, with the benefit of pause and repeat, can dwell on a difficult concept without worrying what a teacher or classmate might think. The next day, the students begin to work through problems in class, as the classroom teacher then becomes a roving mentor who is able to expand upon the lessons from the previous night and work at a deeper level with students at their own pace. In just one year, the number of students in remedial math classes that were deemed to be proficient or advanced nearly doubled and the number of students deemed to be far below basic disappeared.

Khan also showed the progress of one student, a student who moved so haltingly in the beginning weeks that he might have been demoted a level. That student, after finally mastering the topics that did not come easily, excelled so quickly that he finished the semester at the top of his class.

“So the paradigm here,” Khan said, “is that instead of holding fixed the amount of time you have to learn something and then the variable being how well you know it, we’re saying let’s make the variable how long it takes you to master a concept, and let’s make the fixed thing that you’ve really mastered the concept. ... In classrooms today, you can fail an exam, and you’re still expected to move on  to the next concept."

Khan, a former Boston hedge fund analyst, wowed a crowd of 800 educators, advocates and elected officials with a speech at the National Summit on Education Reform in San Francisco that is available online at the Foundation for Excellence in Education.