| The compulsory education mathematics curriculum standards(2011 Edition)pointed out:the students master mathematics knowledge,can not rely on rote,but should be based on understanding;in the basic skills of teaching,and procedures should not only enable students to master the skills,but also to enable students to understand the procedures and steps of the truth.Decimal multiplication is an important part of mathematics in primary schools.The study of multiplication of decimals includes two aspects: "understanding and reasoning" and "Mastering rules".Studies have shown that many teachers pay too much attention to the rule of law,while ignoring the understanding of the rationale.In order to help the students understand the theory and grasp the rules,we must design a reasonable,hierarchical task sequence,in other words,the design of a reasonable learning path.The research questions of this paper are as follows:what is the learning path(hypothesis learning path)for the decimal multiplication(including the decimal multiplication and a decimal multiplication)? How to design and implement the learning path? Such a path is concerned with the understanding of the theory and the rule of law? What are the reasons for the problems in the design and implementation of the learning path? How to form a perfect learning path?We mainly use the method of action research and questionnaire survey.First of all,teachers in class a learning path in accordance with the S A own design teaching;then,teacher S and teacher development guide joint analysis of classroom teaching and puts forward some suggestions for improvement;finally,teachers S redesigned the learning path B,the implementation of teaching in the second class,test the improved effect.Compared with the performance of the students in the classroom teaching and the results of the after class test,we get the optimized decimal multiplication learning path.1 decimal multiplication learning path:From the integer multiplication(a few)into the decimal integer,let the students to solve a cake into an average of ten copies,take one of the two copies.If the graphto express,take a few copies?" Other students mapped 0.2,leading the students to use drawing(visual representation)method to solve the "0.2 x 4 is equal to the number,and then transition to the abstract representation(0.2 words x 4 4 0.2 added),and then explore a pen 3.5 yuan,buy 3 pens,how many money?" The calculation method,guide the students to use the multiplication unit conversion,distributive law,addition calculation,product the same rules to solve the problem,after the cultivation of students' intuitive semi semi abstract ability to solve problems,try to let the students use the methods as much as possible to solve the "ribbon is 0.72 meters long,3 meters long ribbon like?" Provide enough cases accumulated for students,the final push to"1.53 x 4","4+2.56,2.56 x 4",by completing the task to understand and grasp the decimal addition and multiplication decimal why need to align what digital counterpoint,which do not require alignment.Finally achieve the goal of understanding the decimal integer.2 decimal multiplication learning path:First let the students try to use as many methods to calculate the length of 2.4meters,the width of the rectangular area of 0.8 meters,the students use the unit conversion,multiplication distribution law,addition calculation,product constant law to solve the problem.Then also let students use methods as much as possible to find the "1.53 meters long,0.08 meters wide rectangular area",on this issue will appear in the figure is not enough,the students' self summed up "method adds 0 digit enough",through the above two questions for students to summarize:first take the decimal decimal as the decimal integer to decimal by decimal into integer integer multiplication,and then expand to many times before,how many times back to narrow.On this basis,let the students in vertical form "0.56 x 0.04" and "0.06 x0.012",the calculation rules lead students to summarize the decimal decimal by:1according to the integer multiplication calculate the product,then the decimal point;2 decimal point,see the two factors a total number of decimal places,from the number of product of a few decimal points.Then through some students to use judgment reinforcement multiplication rule of fractional error,and finally to "0.006 x50" x 400 "0.00005" two questions for students to understand the end of "0" should bethe first point of the decimal point to 0".Based on the research,we propose the following suggestions:(1)the teaching aim of decimal multiplication is to make the students understand the reason,so teachers should use many kinds of representation,especially the visual representation.(2)at the beginning of the study of decimal multiplication,the decimal multiplication results to the "0"(example: 0.72 x 5)questions are not necessary.Examples like this will only cause students to "point decimal point" confusion.(3)the teacher should go to "0" examples(0.45 x 0.6)whether to adopt,by should be placed in what position,whether the problem of negative influence caused by the students derivation in-depth thinking,proper arrangements for teaching their own path.(4)should be on the original teaching materials,please observe the title of the factor and the product of the decimal number,what can you find?" Questions to "please observe the questions,how do you determine the location of the decimal point?"... |
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