一、引入师:古人没有计算器,常常陷于繁难的大数计算而深感苦恼,他们为了计算出一个行星的位置,往往要耗费几个月甚至几年的时间,庞大的天文数字计算严重地束缚着人类探索宇宙的进程.与此同时,数学家们也感慨:“没有什么比大数的乘、除、开平方或开立方运算更让数学工作者头痛、更阻碍计算者的了.这不仅浪费时间,而且容易出错.”师:让我们一起回到古代,思考一下大数的运算 First, the introduction of division: the ancients did not have calculators, often trapped in the calculation of the complex number of distressed, they calculate the position of a planet, it often takes months or even years, a huge calculation of astronomical figures At the same time, mathematicians are also feeling: “There is nothing more than multiplication, division, square root, or square-root operations for math workers, which gives headache to mathematical workers and discourages the calculators. This is not only a waste of time, but also prone to error. ”Teacher: Let us return to ancient times, thinking about the operation of large numbers