“a+b+c=a+c+b运用了什么运算定律?”在我看来,对于小学数学老师根本就不是一个问题,而就是这个不是问题的问题给了我一个学习和提高的契机,引发了我的很多思考……对加法(乘法)交换律的认识,一直以来,我都是认为交换几个加数(因数)的位置,和(积)不变就是加法(乘法)交换律。直到前几天……(一)先争议,再网络搜索,却无结果。这段时间,我们正在教学人教版小学数学四年级(下)第三单元“运算定律与简便运算”。办公室的一 “In my opinion, the elementary mathematics teacher is not a problem at all, but the problem that is not a problem has given me a study and improvement I have been thinking a lot about the law of addition (multiplication) exchange law, I always think that the exchange of several addends (factor) position, and (product) is the same as the addition (multiplication) Exchange law. Until a few days ago ... (A) the first controversy, and then search the Internet, but no results. During this period, we are teaching the third unit of the fourth grade of PEP (the fourth part of the PEP), ”Computation Laws and Simple Operations". One in the office