Our old site provides free online math flash cards, where a student writes answers by typing in the numbers, an experience quite different from writing on paper. This site is still functional and the URL is http://mathrus.com/oldHome/
However, we have just made an app for iPhone/iPad/iPod Touch such that you simply write answers with your finger, like on paper. It’s so cool that we thought that you might want to check it out. The app is not free but priced at $0.99 — We are a Mom and Pop company and we have to make back the money used to buy a Mac computer to write the app! There is also a video tutorial on our website