I have a adult son who is mentally challenged and in 2001 he was tested and the said he would never get beyond a 1st grade level. Well it has taken a lot of work but he is not doing 2nd to middle 4th grade depending on the subject. If he likes it he will do well if he doesn't he just ignores it. I have learned to us materials he does not like with ides from subjects he does like. That way it is getting better to teach the things he does not like. He likes the math mammoth and I love that fact because Math is one of his don't like subjects.
Thank you for creating the Math-Mammoth it is working even if it takes me a long time to get things through his head.