People have to start from the ground, then first step, second, third and so on to reach their destination floor. Exactly the same way students have to start from Kindergarten, then grade one, grade two and three and so on to reach their math destination. Also, if some of the steps are broken in the staircase, it is still hard to reach the desired floor using those steps. Same way, if you are missing some of the basic concepts from elementary grades, math for you is still hard. Now, the kindergarten, first grade and second grade are like first couple of the steps of the stairs. You can learn this level of math easily, as you can jump enough to take yourself to second or third step of the stairs easily. As it is very hard to reach sixth or seventh step of a stairs by jumping from the ground, exactly the same way to learn grade five or higher grade math is very hard (or impossible) without having the good knowledge of the kindergarten to grade three or grade four math. Now, consider one person is jumping on the ground to reach the third floor of a building. Can this person make it? Never, if he is not Spiderman. For this person, to reach the third floor by jumping is impossible or very hard and finally he gave up saying that it was very hard to reach third floor.
Multiplication worksheets are a quick and easy way to introduce some math revision at home. At first your kids may not appreciate being given extra "homework", but the advantages they will gain from "sharpening the saw" and practicing their math will serve them well; both back in the classroom and on in to later life. With a basic knowledge of Microsoft Excel or Word you can easily make your own math worksheets, but not everyone has that knowledge so it's fortunate that there are many websites dedicated to providing free printable resources, usually in PDF format. You just download, and print _ the only software required is the free Adobe PDF reader.