I'm about to re-commece my OU studies after 12 years absenec and the course this year covers Set Theory and Group Theory. I was born in 1953 and we were never taught these. I've been on YouTube and have picked up some basics, but have wasted lots of time searching blindly. I would be eternally grateful if someone could point me in the direction of useful free structured resources online. The OU will send me materials next year but I'm trying to stay ahead of the game and stave of panic.