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1.
学生初次接触到负数的概念时 ,对理解负数的意义及有理数的运算法则都会产生困难。北师大新世纪版实验教材对解决这些问题的设计思路有这样几个特点 :借助问题情境、从数不够用了的角度引出“负数” ;渗透正负数是“具有相反意义的量”的数学模型的思想 ;从不同的角度表示正负数 ;经过三个层次、借助不同的素材得出正负整数的加法运算法则 ;在应用中体会有理数的作用、熟练有理数的运算 ,以及降低笔算的难度等。这将有助于帮助学生在理解的基础上掌握相关的内容。 相似文献
2.
This study investigated whether the mere knowledge of the meaning of variables can facilitate inquiry learning processes and
outcomes. Fifty-seven college freshmen were randomly allocated to one of three inquiry tasks. The concrete task had familiar
variables from which hypotheses about their underlying relations could be inferred. The intermediate task used familiar variables
that did not invoke underlying relations, whereas the abstract task contained unfamiliar variables that did not allow for
inference of hypotheses about relations. Results showed that concrete participants performed more successfully and efficiently
than intermediate participants, who in turn were equally successful and efficient as abstract participants. From these findings
it was concluded that students learning by inquiry benefit little from knowledge of the meaning of variables per se. Some
additional understanding of the way these variables are interrelated seems required to enhance inquiry learning processes
and outcomes. 相似文献
3.
This study examined changes in 26 fourth-grade students' early conceptions of rational number representations as a function
of receiving one of two curricular interventions. The first group of 12 students received a curriculum that emphasized constructing
knowledge through extended problem solving with a single perspective of the rational number domain based on part-whole relations.
A second group of 14 students received a curriculum that emphasized a more conceptually diverse multiple perspective view
of the domain through problem solving with operator and ratio relations. Analyses of the students' rational number knowledge
before and after the interventions indicated that students in the single perspective group produced organizations of knowledge
that more frequently diverged from a formal domain analysis than those produced by students in the multiple perspective group.
Further, students in the single perspective group increased their focus on superficial surface features. Alternatively, students
in the multiple perspective group demonstrated an increased focus on operations that more frequently reflected the underlying
mathematical relation conveyed by the representation. The findings indicate that an early exposure to more diverse perspectives
of rational numbers assists students in developing more interconnected and viable representation knowledge for rational numbers. 相似文献
4.
When reasoning about rational numbers, people sometimes incorrectly apply principles or rules for natural numbers. Many factors affect whether participants display this natural number bias, including their age and experience, the affordances and constraints of the given task, and even the specific numbers in the given problem. In this paper, we argue that this variability can be conceptualized in terms of dynamic choices among problem-solving strategies. People's strategy choices vary as a function of their repertoire of available strategies and as a function of the specifics of the tasks, problems, and context. Further, we argue that the specific profiles of variability in strategy use that are observed in different participant groups can be conceptualized in terms of the strength and precision of the representations of numbers and operations that people in those groups possess. In our view, the natural number bias arises when people's representations of rational number magnitudes or rational number operations are not sufficiently strongly activated or sufficiently precise to guide performance on a specific task in a specific context. In these cases, participants' more highly activated or more precise representations for natural numbers may underlie and guide their performance. This account suggests that contexts and experiences (including instructional experiences) that help build, strengthen, and activate rational number representations should lead to improvements in performance. 相似文献
5.
王爱奇 《咸阳师范学院学报》2004,19(4):61-62
利用降次求有理数域上两个多项式最大公因式,一方面减少了辗转相除法的运算量,提高了运算的正确率,另一方面,充分体现出辗转相除法的实际意义. 相似文献
6.
高芸 《毕节师范高等专科学校学报》2013,(10):36-43
SDRT的核心概念是修辞关系,认为话语意义受制于话语自身的修辞结构,即话语语段之间或者话语序列之间的逻辑结构,包括叙述、解释、详述、因果、背景、对比、平行、纠正、证据、反证据等。所有的真实修辞关系符合真实修辞关系满足图式。满足图式确保只有当被关系的自变量所标记的内工容和φR（π1,x2）中被明确的“额外的内容”把输入语境和输出语境关联起来时,真实关系才把输入语境和输出语境联系起来。 相似文献
7.
David Weiner Judith Weiner 《British journal of educational technology : journal of the Council for Educational Technology》1996,27(1):5-14
We describe an intelligent mentor for teaching the ability to think scientifically. The student is given an arbitrary starting place in the matrix of knowledge surrounding an area of biomedical research. He/she then proposes hypotheses and supporting experiments which are checked against the knowledge base for agreement, consistency or contradiction. Agreement or consistency results in the report of successful experiments, thus advancing the student's "state-of-the-art." Contradiction results in failure of the experiment to support the hypothesis. In either case, a new hypothesis can then be proposed and tested, each step being potentially contingent on results of the last.
The knowledge base upon which the system operates is a frame-based implementation of the Biomatrix, augmented with pointers to literature citations. Each object (hypotheses, experiments, cells, animals, etc.) is described in terms of its properties and its relations to other objects. Thus, the matrix is represented as a semantic network. Other objects create the relations among the hypotheses, subhypotheses, experiments and other parts of the knowledge base.
This system provides experiential learning at a rate determined by the student, while saving costly resources. 相似文献
The knowledge base upon which the system operates is a frame-based implementation of the Biomatrix, augmented with pointers to literature citations. Each object (hypotheses, experiments, cells, animals, etc.) is described in terms of its properties and its relations to other objects. Thus, the matrix is represented as a semantic network. Other objects create the relations among the hypotheses, subhypotheses, experiments and other parts of the knowledge base.
This system provides experiential learning at a rate determined by the student, while saving costly resources. 相似文献
8.
Floyd R. Vest 《Educational Studies in Mathematics》1971,3(2):220-228
Summary The above catalog contains fifteen headings, each of which indicates a collection of families of models for multiplication and division of whole numbers. The catalog refers to somewhat more than sixteen families of models which are easily distinguished one from the other.Not included in the catalog thus far developed are several interpretations of multiplication and division that are also of interest. Among these are models based on the equivalency of denominations of money and various units of measurement. Other interpretations which are of historical interest are those of McLellan and Dewey [15] and Thorndike [24]. The relation between models of operations on whole numbers and models of operations defined on larger universal sets is also of interest. One aspect of this area of interest is the process of constructing models of multiplication and division of whole numbers from such models by altering the rules of the model or delimiting its universal set. For example, one can begin with one of Diénès' models of multiplication of integers [8, pp. 57–58] and make approapriate adjustments and result in a model of multiplication of whole numbers. Other interpretations developed by Diénès are of interest because they involve concretizations of whole numbers which are operators as opposed to states [8, pp. 12, 30; 9, p, 36].These are a great many strategies available for the use of models in teaching the operations on whole numbers. In one such strategy, an educator can define either multiplication or division on some basis (most likely in terms of a model) and then the other can be defined as its inverse.Another strategy is to define each operation in terms of a different model. For example, one might define multiplication in terms of the repeated addition model and division in terms of the repeated subtraction model.Still another type of procedure involves a multiple embodiment strategy in which several interpretations are taught as representing each operation.The choice of a particular strategy would depend upon a great many factors. Some of the factors would be the type of culture and students for which the program is written, the psychological assumptions adopted by the writer, and the writer's knowledge of the domain of models for the operations as well as their relation to the abstract mathematical domain which they represent. This article has contributed to a basis for intelligent decisions in this area by presenting a characterization of the domain of models for multiplication and division of whole numbers and their relation to the abstract operations. 相似文献
9.
Janet Teeple 《Quest (Human Kinetics)》2013,65(1):66-70
A good curriculum structure will be both rational and coherent. It will be based upon values as well as reflect them. Further, it will place them into a justifiable order of priority. The term physical education, apart from its implicit dualism and ambivalence of meaning, has failed to differentiate satisfactorily between intrinsic and instrumental objectives and has not spelled out clearly what the educational part of the term refers to. The threedimensional model of the movement curriculum, it is argued, is able to do this and at the same time provide a framework in which such values as skill, knowledge, fitness, and pleasure can be appraised. 相似文献
10.
Floyd Vest 《Educational Studies in Mathematics》1973,5(1):147-155
Summary From a general and systematic point of view, this article has attempted to answer the questions, How do models and equations relate?, How does one teach this relationship? In the process, a systematic procedure for analyzing this task of teaching operations with the use of models and developing teaching strategies has been demonstrated. In applying the several concepts of this article to the preparation of a lesson, the teacher can (a) choose models and a family of equations, (b) choose an analysis of the equations into constituent parts involving family or equation levels, (c) choose an analysis of models into their critical attributes, and (d) plan a strategy utilizing direct correlates or oblique correlates for connecting the equations and models at a general or instance level. On the basis of such planning, the teacher will develop with a class a knowledge of the parts of the equation, the critical parts of the model, and correlates for connecting the two.Without utilizing these concepts, teachers have been found to attempt the introduction of the connection between an equation and a new model simply by placing the illustration (instance of a model) and equation together on the chalkboard and reading the equation. (This may seem absurd, but the author is aware of a film designed to present exemplary teaching in which this is done and has observed student teachers overlooking the necessity for carefully connecting the model and the equation.) Such practices as these in the context of the common telling-teaching process suggest that teachers' commentaries should provide extensive analyses and direct correlates [7].The four concepts (correlates, analysis of models and families of equations at the general and instance level, oblique correlates, and adequacy of analysis of models and equations) have been referred to as general concepts. They are general in the sense that they can be applied to the use of models of any operation. As was pointed out earlier, this level of generality extends to more than forty families of models of operations and inverse operations on whole numbers. It also extends to the use of models of operations in other number systems. 相似文献
11.
The foundations for more advanced mathematics involve a good sense of rational numbers. However, research in cognitive psychology and mathematics education has repeatedly shown that children and even adults struggle with understanding different aspects of rational numbers. One frequently raised explanation for these difficulties relates to the natural number bias, i.e., the tendency to inappropriately apply natural number properties to rational number tasks. This contribution reviews the four main areas where systematic errors due to the natural number bias can be found, i.e., their size, operations, representations and density. Next, we discuss the major theoretical frameworks from which rational number understanding is currently investigated. Finally, an overview of the various papers is provided. 相似文献
12.
It has been assumed, on historical and psychological grounds, that the concept of irrational numbers faces two major intuitive obstacles: a) the difficulty to accept that two magnitudes (two line segments) may be incommensurable (no common unit may be found); and b) the difficulty to accept that the set of rational numbers, though everywhere dense, does not cover all the points in an interval: one has to consider also the more rich infinity of irrational points. In order to assess the presence and the effects of these obstacles, three groups of subjects were investigated: students in grades 9 and 10 and prospective teachers.The results did not confirm these hypotheses. Many students are ignorant when asked to classify various numbers (rational, irrational, real) but only a small part of the subjects manifest genuine intuitive biases. It has been concluded that such erroneous intuitions (a common unit can always be found by indefinitely decreasing it and in an interval it is impossible to have twodifferent infinite sets of points [or numbers]) have not a primitive nature. They imply a certain intellectual development. 相似文献
13.
陈晓杰 《常熟理工学院学报》2011,25(8):39-42
阐述了单纯形法和对偶单纯形法的思想与一般解法,在生产问题的线性规划模型中,利用价值系数,资源系数,技术系数的一些关系和对非基变量检验数产生的影响,通过一些特定变量的进出基运算,使得单纯形法的一般求解步骤减少,运算得到简化． 相似文献
14.
The relation between performance in phonemic segmentation and reading and writing ability is discussed. Not much is known about how segmentation is carried out and which word properties influence performance. Therefore, effects of word properties (length, CV structure, syllabic structure, meaning) were investigated in two experiments. Strong indications were obtained that an onset-rime distinction is relevant for the process of segmentation. The meaning of a word appears to have no influence. The decentration hypothesis can therefore be abandoned as an explanation for segmentation difficulties. Effects of length and syllabic boundary can be explained by the (disruptive) effect of consonant clusters, which are not only difficult to segment themselves, but also adversely affect the processing of segments earlier in the word. This leads to the conclusion that a simple, strictly serial model for segmentation cannot be adequate. The results furthermore suggest that an articulatory rather than a phonological code is the object of segmentation. 相似文献
15.
陈志伟 《沙洋师范高等专科学校学报》2007,8(6):82-83,87
人们在描绘对象时往往会产生各种各样的错觉,有些错觉会破坏造型上的准确度,而有些错觉却能有力的强化艺术形象,体现出艺术上的准确度,并能使画面趣味横生。过于准确、刻板、理性的造型,反而使画面索然无味,并将富于感情的错觉扼杀于摇篮里,从而降低了绘画作品的格调。 相似文献
16.
管乐 《湖北第二师范学院学报》2014,(12):130-132
多模态隐喻理论为隐喻学这一研究热点提供了新的视角,本文从多模态隐喻的角度来分析2014年巴西世界杯吉祥物和会徽,通过视觉模态、颜色、文字等多种模态的综合运用详细分析了2014年巴西世界杯吉祥物和会徽所体现的多模态动态构建机制,在体现隐喻意义的同时,如何通过合理协调多模态因素体现2014年巴西世界杯的理念. 相似文献
17.
学生的理解水平、认知发展水平是制定课程目标的重要依据。只有厘清、界定了学生的实际理解水平,才能寻求、探查到一个多数人都能达到的目标层次,制定出适切的课程目标。以有理数乘法运算为例,学生对有理数乘法运算的理解具有层次性与有限性。由低到高,理解的三个水平为程序理解、直观理解、抽象理解。学生对有理数乘法运算的理解是非常有限的,原因在于知识的超验性与学生认知发展的层次性。对照义务教育课程标准发现,课程目标要求偏高,课程目标表述模糊。因而,课程目标需要基于学生的理解水平,具有层次性、明确性、适切性。 相似文献
18.
黄易青 《北京师范大学学报(社会科学版)》2003,(5):117-124
上古汉语的词汇及其意义有其内在系统,其中的重要内容之一就是在词的引申义及同源词意义中呈现出大量的、有系统的、有规律的、相对立而又相通的对应关系——对立统一关系。这种意义关系形成的原理,可以从人所认识的客观事物关系、运动发展规律、认识原理和词义引申规律四方面得到理性解释。在这些原理的探讨中,提出了词义内涵量化分析的方法——两极之中两种维度的量变运动描写。 相似文献
19.
王洲明 《四川师范学院学报》2005,(3):1-5
人类思维认知水平与文学创作有内在联系。汉代离古未远，汉代文学代表作品的辞赋，表现出明显的理性思考的轨迹。汉大赋中的理性思考既表现为对儒家政治、道德的追求，又表现为讽谏意识的增强、讽谏内容的增多。汉代抒情、说理赋对道家自然无为思想的理性思考，具体落实在个人行藏出处的人格建构上，体现出对自然本真人格的追求。儒、道的合一影响及汉代士人人格的形成。 相似文献
20.
In this study we investigate whether the process of Attraction, Selection and Attrition as described by Schneider (1987) is already operative prior to labor market entry, i.e., in the educational phase of careers. We focused on selection with regard to the locus of control personality trait because of its firm conceptual and empirical relevance in both content and process of choice. Specific hypotheses were proposed as to the sorting of different personality types in study programs leading to different prospective professional careers. The study was carried out in a sample of 158 Austrian students. We found strong support for our hypotheses in that (1) personality predicted specific study choices and (2) personality predicted different levels of rationality in the choice process. In addition, the findings also suggest that tighter matches between personality and study programs could be observed for students making rational choices. The results indicate support for the validity of the ASA model in educational choice, provided the use of meaningful individual differences. Several promising avenues for future research are identified. 相似文献