Khan Academy — free lessons for school and adult learners

Khan Academy provides free, high‑quality lessons in maths, science, computing and humanities for school‑age pupils and adult learners; resources include videos, practice exercises and progress tracking. It is free for everyone worldwide, including UK residents, and you can sign up or use resources without payment; teachers and parents can set up class or student accounts. Content is self‑paced and aimed at supplementing school learning or lifelong study with no subscription required.