Here are the websites for the Holt Mathematics Course 1 and Course 2 programs. There are many useful tools on the site. If you need help you can go to homework help and there is step by step directions to solve many of the problems in the book. There are also tools and resources to help parents.
Holt Mathematics Course 1 http://go.hrw.com/gopages/ma/msm1_07.html
Holt Mathematics Course 2 http://go.hrw.com/gopages/ma/msm2_07.html
Other useful sites for kids and parents: