Khan Academy 

If you want a learning app to recommend to just about anyone, this is it. Khan Academy is a nonprofit platform with a huge library of video lessons and interactive exercises covering K–12 and early college math, science, economics, history, test prep, and more — all completely free.

You can drop into a topic like algebra or world history and work through bite-sized lessons at your own pace. The app tracks your progress and uses a mastery system, so you aren’t just passively watching videos; you’re actually practicing and leveling up your skills as you go.

Khan Academy is also leaning heavily into AI with Khanmigo, an AI tutor and teaching assistant that guides you through problems instead of just giving answers.

Whether you’re restarting math from the ground up, helping your kids, or just filling gaps you missed in school, Khan Academy is one of the best apps to help you on your journey.