乘法分配律是在学生学习了加法交换律、结合律及乘法交换律、结合律的基础上教学的。乘法分配律是乘法三个运算定律中最难掌握的一个。原因有二,一是学生的感性认识比较少,平时学习中虽然在一题多解中见过这样的形式,却对它们之间为何有这样的关系不理解;二是乘法分配律形式变化比较大,学生原 Multiplication distribution law is in the students learn the addition exchange law, combined with the law of law and multiplicative exchange law, combined with the law based on teaching. The law of multiplication distribution is the most difficult one to grasp in the three laws of multiplication. There are two reasons for this. First, students’ perceptual awareness is relatively small. Although in normal learning, they have seen such a form in a multi-pronged solution, they do not understand why they have such a relationship. Second, Big, original student