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.
But another person used the stairs to reach the same floor. This person found it very easy and reach there with little effort. Compare this person to a student who knows all the basic concepts learned in elementary grades. To learn grade six or grade seven math for this student will be easy. But there is another student in grade six and doesn't know the lower grade math concepts such as, times tables, factors or number system. This student is in the same situation as the person, who is jumping to reach third floor from the ground level. From the example it is very clear that mathematics in each grade have the same importance. So, you need to be focused on math in all the grades on all the basic concepts. Ask your teachers lots of questions. Keep asking until you are not clear about the concepts or topics you are working on.