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.
Math worksheets don't provide immediate feedback _ Most teachers are familiar with the long delay between when students complete a worksheet, and when they get their correct page. Most don't get anything back until the next day or the next week. In the meantime, the students continue to practice incorrectly. It's no surprise that immediate feedback has been shown to increase student performance and diligence. Unfortunately, math worksheets have no mechanism for keeping a student from moving to the next problem until after they demonstrate understanding. Good curriculum software can address this issue by giving students instant responses and strategic feedback. The use of visual cues and auditory feedback helps students quickly recognize their fraction errors and self_correct. This just_in_time feedback system eliminates practicing incorrectly, while promoting self_correction and independence.