论文部分内容阅读
“九义”小学数学第五册“两步应用题”,是本册教学重点之一,是第四册中两步应用题的延续,又是以本册“笔算除法”中的简单倍数应用题为基础进行教学的。这部分内容按照基本数量关系相同,解题思路相近,并遵循由易到难、循序渐进的原则编排为四组。第一组应用题都必须先求出两个数的和,再求第三个数;第二组应用题基本数量关系都是比多(少)求和(差)与求几倍数相结合。这两组应用题中都有三个已知条件。第三、四两组应用题中已知条件都只有两个,求解时其中一个条件需重复使用,两组题的基本结构相似。第四组又是第三组应用题的逆向题,难度逐步增大。可见前两组应用题是教学重点,后两组应用题是教学难点。每组应用题的编排都是先复习一道与例题相关的一步应用题,将题中某一条件变化一下便引入两步应用题(例题),引导学生思考先求什么,求解后,再运用“想一想”出示例题的变式题组,最后设置了“做一做”和练习。
“Nine justice” elementary school mathematics fifth volume “two-step application problem” is one of the teaching focus of this book is the continuation of two-step application in the fourth book, but also with the book “pen division” in the simple multiple application Title as a basis for teaching. This part of the content according to the same number of the same relationship, problem-solving ideas are similar, and follow from easy to difficult, step by step, the principles of the four groups. The first group of questions must first find the sum of the two numbers and then find the third number; the second group of questions are the basic number of questions than the more (less) sum (poor) and seek several times combined. There are three known conditions in both sets of questions. There are only two known conditions in the third and fourth groups of application questions, and one of the conditions to be solved for reuse is repeated. The basic structure of the two groups of questions is similar. The fourth group is the reverse problem of the third group of application questions, the difficulty increases gradually. Can be seen that the first two groups of application questions is the teaching focus, the latter two groups of questions is difficult teaching. The arrangement of each set of application questions is to review a one-step application question related to the example question, introduce a two-step application question (example) to change a certain condition of the question, to guide students to think first about what to ask, and then to solve the problem by using “ Think about it ”to show the variant of the example group, finally set“ do one ”and practice.