How many kids in school have done their homework? Again this can be answered in several ways: in percentages, 70%; or in ratio, 7:10; Both of these mean out of ten kids in class there are seven good ones who did and three not-so-good ones who didn't. The bottom line is that kids learn math much better when it makes sense.
Another important point I keep in mind is that I never want this regular math review time to take up and hour of class time. I want it to be quick but effective. This is not instructional time, but time for the students to review material they have already learned.
Why use free math worksheets? Easy. These worksheets can save you a lot of time and money and when you're a busy homeschool mom teaching several children, this means a lot.
However for the most part, when a worksheet is needed to help drill down a procedure, standard, or lesson, its effectiveness can and will vary.