一、建模点分析1.比的意义的模型本单元是在学生已经理解了除法的意义和基本性质、分数的意义和性质以及分数乘除法的基础上学习的。由于比与分数、除法有着密切的联系,把比放在分数、除法之后进行学习,既加强了知识间的内在联系,又为以后学习比例及相关知识打下基础。该部分内容是以学生熟悉的人体为载体,呈现了头长、臂长、腿长、身高几个信息,简单明了、一目了然。借助“怎样用算式表示赵凡的臂长和腿长的关系呢?”等问题,引入对比的意义的学习。借助信息窗提供的信息,学习 First, the modeling point analysis 1 than the meaning of the model This unit is the student has understood the meaning of the division and the basic nature of the meaning and nature of the score and the fractional multiplication and division based on the study. As compared with the score, division is closely linked to the ratio on the score, the division after the study, both to strengthen the intrinsic link between knowledge and lay the foundation for future study of the proportion and related knowledge. The part is based on the familiar human body as a carrier, showing the length of the head, arm length, leg length, height, a few pieces of information, simple and clear, at a glance. With the help of “how to express Zhao Fan’s arm length and leg length relationship?” And other issues, the introduction of comparative significance of learning. Use information provided by the information window to learn