教材简介这节课是在学生掌握了常见数量关系、运算律、周长与面积计算等知识基础上安排的,让学生初步理解并学会用字母表示数,以及用含有字母的式子表示简单的数量关系和计算公式。目标预设1.让学生理解和掌握用字母表示数的方法,知道含有字母的式子既可以表示数、数量,也可以表示数量关系。2.会用字母表示数量关系,能求含字母的式子的值。 This course is based on the students grasp the common relationship between quantity, arithmetic law, perimeter and area calculation based on the knowledge of the students to understand and learn to use the number of alphanumeric, and with the letters of the formula that simple Quantitative relationship and calculation formula. Objectives Preset 1. Let students understand and master the number of alphanumeric methods that contain letters can be expressed in terms of number, quantity, can also represent the quantitative relationship. 2. will use the letters that the number of relationships, can find the value of the formula with letters.