A lot of the websites charge high dollar amount for these math worksheets. Considering your willingness to spend the high dollar, you run in to a new problem - the uniqueness of the material, a lot of websites offer sheets packed with identical problems leading the child to almost rote memorization of the problems and solution. This leads to deprivation of student and his/her ability to solve the problems logically. And some websites offer sheets in portable document format. And to open such sheets you are forced to download special software.
Today we all know that benefits of math are considerable. Math is not a subject one learns by reading the problems and solutions. American children have very little practice with multi-step problems, and very few opportunities to think their way in to and through problems that dont look like all the others. With a packed curriculum and the increased emphasis on testing, our children are taught tons of procedures - but procedures disconnected from when to use them, and why. Sustained thinking - the key ingredient to math success - is painfully absent in too many math classes.