The Khan Academy is a not-for-profit online learning project that aims to provide a free, quality education to anyone, anywhere.
You can take advantage of their bitesize video tutorials and challenges too, to boost your subject skills for school or learn something totally new.
Subjects include: Maths, History, Economics, Sciences and Computer Programming.
Start right at the beginning or jump in at a higher level, it's up to you. The site lets you track your progress and pick up achievement badges as you go.
You can access lessons online or via the Khan Academy App.