世界上最早提出正负数加减法法则的,仍然是我国的《九章算术》.当时叫做“正负术”,其中说到的加法法则是“异名相除,同名相益.正无入正之,负无入负之”.减法法则是“同名相除,异名相益.正无入正之,负无入负之”.这里,“同名”、“异名”就是我们今天讲的“同号”、“异号”,“除”、“益”就是“减”、“加”.加法法则的意思是说:两数相加时,若二数同号,则 In the world, the first to add or subtract the law of positive and negative numbers is still our country’s “Nine Chapters of Arithmetic.” It was called “positive and negative techniques” at that time. The addition method mentioned was “separating different names from each other, and the same name was added. Into the positive, negative and negative.“ Subtractive law is ”Divided by the same name, different names and benefits. Is not in the positive, negative and negative.“ Here, ”same name“, ”same name“ is what we are talking about today. ”The same number“, ”unique“, ”except“ and ”benefit“ means ”decrease“ and ”plus." The addition rule means to say that when two numbers are added, if two numbers are the same, then