Khan Academy filled the gaps from my inconsistent public schooling (moved a lot as a kid). Used to think I was just dumb (I might still be lol), but turns out missing some of the early math concepts is extremely destructive to later learning. Fill the gaps and everything else becomes so much easier.

I hear tell Sal Khan is hiding out in the Bay Area somewhere, really wish I'd bump into him in a bar so I can grab his tab or something. Dude's a hero to me.