谈新世纪版教材对"有理数及其运算"引入的处理

学生初次接触到负数的概念时 ,对理解负数的意义及有理数的运算法则都会产生困难。北师大新世纪版实验教材对解决这些问题的设计思路有这样几个特点 :借助问题情境、从数不够用了的角度引出“负数” ;渗透正负数是“具有相反意义的量”的数学模型的思想 ;从不同的角度表示正负数 ;经过三个层次、借助不同的素材得出正负整数的加法运算法则 ;在应用中体会有理数的作用、熟练有理数的运算 ,以及降低笔算的难度等。这将有助于帮助学生在理解的基础上掌握相关的内容。

On how new century version textbooks introduce "rational and operations"

When first meet negative numbers, students have difficulty understanding both the meaning of negative numbers and the rules of operation between rational numbers. The new century textbooks for piloting program by Beijing Normal University Press have following characteristics in designing the contents, regards these problems:With the help of the real world problem situation, the concept of negative numbers is introduced from the angle of positive numbers alone are not enough for using now. To infiltrate that positive and negative numbers are mathematical models of those quantities with opposite meanings.Using different materials and by three different levels, the adding rules between positive and negative numbers are introduced.The students understand the rational numbers and learn the operations by application.Reducing the degree of difficulty in the way of pencil and paper calculation. These will of great help in students' mastering the contents of concern on basis of understanding.