Great, fun and free math worksheets should be able to present a mathematical problem in different ways. Math is after all nothing more than a numeric expression of some of life's simplest questions:
Subtract 1-, 2-, or 3-digit numbers from 3- and 4-digit number with/without renaming
Point is, whatever it takes to get students actively involved with the reviewing process where they are not bored and effectively reviewing grade level material in order to prepare them for state or quarterly assessments.
Homeschool worksheets are far more than busy work. They are an important part of making sure that the concepts you teach in your home school stick with your child. Just make sure you have a good source for providing the worksheets, and that they're the right ones for your kid or kids.