在初中数学竞赛、中考等各类考试中,经常遇到一些数字较大、项数较多、次数较多、结构复杂的有理数计算问题,若按常规的运算顺序和运算法则计算十分复杂,但只要注意观察题目的特点及结构特征,找出规律,选择恰当的方法技巧,探寻巧妙简捷的解法,常能突破常 In junior high school math competitions, senior high school entrance examination and other examinations, we often encounter some numbers with large numbers, more items, more times, and complicated structures. Rational numbers are often complicated to be calculated according to the usual operation sequences and algorithms As long as the attention to observe the characteristics of the subject and structural characteristics, to find out the law, select the appropriate method skills to explore clever and simple solution, often breaking the often