小学数学中的许多概念、性质、运算、思路都具有可逆性,如加法与减法,乘法与除法,增加与减少,扩大与缩小,多与少,倍与率,计量单位的化与聚,正比例与反比例,都表现为处于同一整体结构中的两种相逆的意义。数学知识的这种可逆性的客观存在,要求学习者逐步具备“心理过程的可逆性”,即逆向思维的过程和能力去认识和把握它们,以求从知识的相互关系上把握知识结构,从整体上理解知识的 Many concepts, properties, operations and ideas in elementary mathematics are reversible, such as addition and subtraction, multiplication and division, increase and decrease, expansion and contraction, more and less, times and rates, and units of measurement and proportion And inversely proportional, all show two opposite meanings in the same overall structure. The objective existence of such reversibility of mathematical knowledge requires learners to gradually possess the “reversibility of psychological process”, that is, the process and ability of reverse thinking to recognize and grasp them in order to grasp the knowledge structure from the mutual relations of knowledge. The whole understanding of knowledge