【教学内容】北师大版四年级上册第48～49页。一、课前思考乘法分配律的教学是在学生学习了两位数乘两、三位数乘法以后,学生已经熟练掌握了乘法意义的基础上进行学习的,这时学生虽然学习了二、三步的混合运算,但解答的形式不相同,学生很难找到学习新知的切入点。而运用乘法分配律进行简便运算的变式又多, 【Content】 Beijing Normal University version of the fourth grade on the first 48 ~ 49 pages. First, pre-class thinking multiplication distribution law of teaching students learn the double-digit multiplied by two or three, multiplication, the students have mastered the significance of multiplication based on the study, when students learn two or three Mixed computing steps, but the answer is not the same form, students find it hard to find a new entry point. The use of multiplication distribution law to simplify the operation of many variants,