Mathematics skills can improve with just one technique _practice! Most of the children end up petrified of numbers and number games because of lack of appropriate knowledge. All this is a result of poor teaching mechanics. The vast school curriculum does not teach the children the perfect way of learning the subject. It's only proper practice and regularity that can make a student reach perfection! Do worksheets help a child?
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.