教学目标1.借助年龄问题、青蛙儿歌等生活情境,引导学生经历把简单的变化规律用含有字母的式子(加减法、乘法)进行表达的抽象过程,并理解含有字母的式子既可以表示一个数,也可以表示数量之间的关系。2.在具体情境中,借助观察、比较、想象等方法体会“变”与“不变”的关系,渗透函数思想和模型思想。3.初步学习用代数符号语言(含有字母的式子)表示的方法,体会其优越性,培养符号意识,感受数学的价值。 Teaching Objectives 1. With the aid of age and frog children’s songs and other life situations, students should be guided through the abstract process of expressing simple variation patterns in alphabetical formulas (addition and subtraction, multiplication) and to understand that the formula containing letters Represents a number, it can also represent the relationship between the number. 2. In specific situations, through observation, comparison, imagination and other methods to understand “change ” and “unchanged ” relationship, infiltration function and model ideas. 3. Preliminary study Algebraic symbolic language (including letters of the formula) that method, realize its superiority, cultivate symbolic awareness, feel the value of mathematics.