If you do want to produce your own worksheets and don't have the Microsoft software, you can download free tools like OpenOffice or use an online word processor or spreadsheet such as the free Google Docs which help you do similar tasks. You just need to create a table with as many rows and columns as you need and then type in some numbers before printing it off for your children to practice _ depending on the level of complexity choose single digits or multiple digits. If you're not sure what level to start at, aim low, start with easy numbers and see how your child goes, the self_esteem boost they'll get from acing the first worksheet will give them confidence for more difficult math problems.
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.