运算定律教学，走出“迷惘”之境——对“运算定律与简便计算”的探索与再思考

Teaching with Operation Laws, out of the Realm of the ＂Lost＂ ——Exploration and Re-thinking about ＂Operation law and simple calculation＂

“运算定律与简便计算”是人教版教材第八册的内容，主要包括加法交换律、加法结合律、乘法交换律、乘法结合律，乘法分配律，以及这些运算定律的简单运用。在教学中，笔者发现学生普遍出现“一学就会，一做就错”，“简便不简单”的现象。于是笔者重审教材，回望教学。下文笔者侧重以变化形式多，学生最难以掌握的乘法分配律教学为例，谈谈在教学中的一些思考与实践。

＂Operation law and the simple calculation＂ is PEP eighth volumes of the textbook content, including the addition commutative, associative law of addition, multiplication, commutative, associative law of multiplication, multiplication distributive law, and the simple use of the law of computing. In teaching, the author found that students were generally ＂To learn, one can do wrong＂ and ＂simple but not easy＂ phenomenon. So I retried the materials, look back to teaching. Below, the author focus on variations, the most difficult for students to grasp the distributive property of multiplication for example, talks about some of the thinking and practice in teaching.