I'm going to have to brush up on my maths, The Teenager is up to quadratic equations now so I can't just look over her shoulder and patronisingly walk her through her homework any more, and after all my years of telling her I'm a maths genius I kind of have to back it up when she gets up to GCSE revision in like a year's time
Khan academy is a site I recall hearing good things about, and I see there's an app for it. Any better recommendations? I'm not looking for degree-level physics, I just want to remind myself of the basic formulae for the elementary level trigonometry, calculus etc and hopefully it will all come flooding back...