These days, kids use YouTube to receive fun lessons. I have seen many parents who buy a tablet for their kids and let them watch hours and hours of youtube videos. It's good as kids will no longer move around and will stop bothering their parents. But I must argue the quality of education on Youtube. That's why such websites come into play. There are online games, courses, videos and teachers. I'm not in the US, but I can still use their facilities. I thank them for it. I also wish they could add a scoring system on their website; something like stars that kids get when they learn new songs or match calculations. Critical thinking is also very important, so maybe riddles would be nice to see here. The kids of the future must learn to solve problems.