数学家祖冲之

　　祖冲之(公元429～500年)，南朝宋齐时期人。他年轻时就学问渊博，尤其喜爱数学。

　　祖冲之在数学方面的成就，是求出了比较精确的圆周率。圆周率是圆的周长和直径之间的比例，中国古代很早就知道这个概念，但不太准确。祖冲之总结前人经验，决定利用三国时候刘徽的“割圆术”来求圆周率。可是，那时运算的工具是竹棍，对于九位数的运算，要经过130次以上的反复计算，而且又容易出错。祖冲之每算一次，至少重复两遍，直到几次的结果完全相同才行。经过刻苦运算，他一直算到了12,288边形和24,576边形，终于得出圆周率大于3.1415926，小于3.1415927的结论。

　　祖冲之是世界上第一个把圆周率算到小数点后7位数字的科学家，900年后，一位中亚的数学家推算到小数点后16位，才超过了他。除此之外，祖冲之编写过一部《缀术》，收集了他研究数学的主要著作。唐朝时把《缀术》列为数学课的主要教科书。

　　Zu Chongzhi, the Remarkable Mathematician

　　Zu Chongzhi (429-500 AD) lived in the period of Song and Qi of the Southern dynasties. He devoted himself to study in his youth, being especially fond of mathematics.

　　Zu calculated the ratio of the circumference of a circle to its diameter at between 3.1415926 and 3.1415927, a figure which was not surpassed in accuracy until 900 years later. In fact, Chinese scientists of previous dynasties had already made their own rough calculations of the ratio. Zu Chongzhi compiled his major achievements in mathematics into a book called Zhuishu, which became the main textbook on mathematics in China during the Tang Dynasty.