在数学竞赛中,常会遇到这样一种题型:新定义一种运算或一个数学符号,然后按新给的定义和符号来解题,这种题的难度不一定很大,但它能达到训练和检测参赛者的思维能力、应变能力和演算能力的目的,便于选拔数学尖子.下面我们就来研究这方面的题目. In mathematics competitions, you often encounter a question type: a new definition of an operation or a mathematical symbol, and then solve the problem according to the newly given definition and symbol. The difficulty of such a problem is not necessarily large, but it can be achieved. The purpose of training and testing contestants’ thinking ability, resilience and calculation ability is to facilitate the selection of mathematical tops. Here we will study the topic.