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等量代换是数学中常用的一种方法。运用这一方法思考问题,对帮助学生理解算理、拓宽解题思路、发展思维颇为有益。一、运用等量代换的方法,帮助学生理解算理。在低年级的“两位数减一位数”一节教材中有这样一道例题:“学校里养了7只黑兔,12只白兔。白兔比黑兔多几只?”这道题对一年级学生来说,理解算理是教学的重点和难点。为了减小思维的坡度,教材安排了一幅小朋友在拔河的图画,左边有5个小朋友,右边也有5个小朋友,要求学生认识左边的小朋友和右边的小朋友人数“同样多”,从而出现5=5,帮助学生建立“等量”的概念。学生有了这一知识基础,再教上述例题时,就可借助图形,拿一只只黑兔和一只只白兔一一对应地排列起来,白兔多,
Equivalent substitution is a commonly used method in mathematics. Using this method to think about the problem is quite beneficial for helping students to understand the theory, broaden the way of solving problems, and develop their thinking. First, the use of equivalent replacement method to help students understand the arithmetic. In the lower grades of “double-digit minus one-digit” textbook has such a case: “The school raised seven black rabbits, 12 white rabbits. For first-year students, understanding arithmetic is a key and difficult teaching point. In order to reduce the gradient of thinking, the text arranged a drawing of children in the tug of war, there are five children on the left and five children on the right, asking students to recognize that the number of children on the left and the number of children on the left are ”as many as possible“ 5, to help students establish the concept of ”equal". Students have this knowledge base, and then teach the above example, you can use graphics to get a black rabbit and a white rabbit one by one corresponding to the arrangement of more white rabbits,