Khan Academy — free lessons and practice for learners of all ages

Khan Academy provides free, ad‑free lessons, instructional videos and practice exercises in maths, science, computing and humanities aimed at school‑age and adult learners. The platform is free for everyone worldwide; UK students and parents can create free accounts, follow curricula‑related content and track progress. No payment or card is required — just register on the site or app, choose subjects and start working through practice exercises and video lessons at your own pace.