My son had been in advanced math since elementry school but several of his friends went to the kumon program.
He seemed very impressed with their math skills. I decided to put him in the same program. although I am not too impressed with the programm it had helped my son to calculate quicker and with less mistakes. The cost is over $100.- a month but there has to be a free version of this through an online educational website or so.
If anyone has any recommendations on the free version, feel free to post it on the blog.