to math education, says khan, is that students carry on gaps in their knowledge throughout their math careers. making it hard to get the more advanced concepts. the key to overcoming that problem is to let students learn at their own pace. khan academy offers students a quiz after each video, and they can't pass a level until they get ten out of ten questions right. >> let everyone learn at their own pace. only move on to a concept once they've gotten to a certain level of proficiency or a mastery on a base level. >> if we let students learn at their own pace, what does that do to the traditional classroom model? it's turned upsidedown. which is exactly what we need to do. last fall, los altos, california, agreed to use khan academy in five classrooms. >> show me what that looks like as a number. >> kami thordarson allowed her students to experiment with the program to see what it could