The school that set my son up on this had no idea. What she was doing. He's trying to do classes he hasn't yet learned and the classes are 2 grades above his. There are no textbook to refer to and lessons are not explained well. I contacted his teacher where he was attending but she was no help and said they didn't have any teachers to help. This should be taken down as it's not a teaching site for things not yet learned elsewhere. I'm out a lot of money purchasing many books which help with nothing.