Khan Academy

Khan Academy covers math, science, computing, and humanities from primary school through university, free, as a non-profit — and its Khanmigo AI tutor guides students through problems with Socratic questioning rather than just handing over the answer. Well over 150 million people have used it to learn at their own pace, and it remains one of the most credible examples of AI tutoring actually improving how students learn rather than just doing the work for them.