I purchased this for dd7(DYS) at the time she was 6, she goes in spurts on if she is interested in math or not when she is I pull it out. I love it, because it has a cute story about a 5 year old at college at the end of each chapter there are 9 questions to go over what was learned, and she understands (matter of fact she has corrected me when I was wrong,lol it's been a while since I've done math like this) I have the fractions book. it was $19.00 go to :
http://www.stanleyschmidt.com/FredGauss/index2.htmlIf he's mathy I think he'll enjoy it, and even if he's not ready for it yet, when he is you'll have it handy
Best wishes