有理数运算是初中数学中的基础运算,它的用途很广,在这里,我们有必要介绍一下有理数运算中的几种新题型.一、速算型1.奇数个等差的整数相加.例1计算:2 003+2 006+2 009+2 012+2 015.解析:这个算式的特点是:(1)几个加数依次相差3;(2)加数的个数为奇数.满足这两个条件,就可以直接用中间一个数乘以加数的个数,得到几个加数的和.原式=2 009×5=10 045. Rational number operation is the basis of mathematics in junior high school operations, its use is very wide, here, we need to introduce some of the rational number operation in the new types of questions. 1 Calculated: 2 003 + 2 006 + 2 009 + 2 012 + 2 015. Analysis: The formula is characterized by: (1) a few addends differ by 3; (2) the number of addends is odd Two conditions, you can directly use the middle of a number multiplied by the number of addends, get the sum of several addend. Original = 2 009 × 5 = 10 045.