Experimentation on willing participant

I decided to use my 9 year old son as an experiment.  I took him to a couple of the sites recomended to help kids with math and reading skills.  He had a great time!  There were a couple sites that he has already been to.  He likes Poptropica.  I observed him as an educator to see what his reaction was while he was playing the games.  We did one were he figured out tips by percentage on a resturant bill.  He was pretty good at it.  I found it interesting that he really didn't care that he was learning math and reading. He just seemed to be having fun on the computer.  I'm going to encourage some of these sites for him to try when it's his screw around time on the computer and see how that works out.