定时，自我评分，算术练习网页。

A self-contained XHTML/Javascript web page providing timed, self-scoring, practice of the four basic arithmetic operations. Designed based on criteria used in my daughters" grade school. I offered it to the school and they snapped it up, so hopefully others will find it of use too. May be saved to the local machine and opened in any Javascript enabled web browser. Works equally well when hosted from a web server. Tested on Apache, MSIE, Firefox, and Chrome.