THE INFLUENCE OF TEACHERS’ PRESENTATIONS ON PUPILS’ MENTAL REPRESENTATIONS

Teachers use a variety of external representations to communicate mathematical ideas to their pupils. This paper reports a preliminary study of the internal mental representations that 6- and 7- year-old pupils form as a result of their interactions with the teacher's verbal, written, pictorial and concrete material representations, involving two-digit numbers and operations on them. The results presented here concern the picture-like mental representations that pupils use in performing two-digit calculations mentally. The evidence suggests that pupils seldom spontaneously visualise teachers’ representations or attempt mental manipulation of visual images to help with calculation. Pupils can, however, have mental representations which reproduce some aspects of the teachers’ representations.     

A diagrammatic view of the equals sign: arithmetical equivalence as a means,not an end

It is recommended in the mathematics education literature that pupils be presented with equality statements that can be assessed for numerical balance by attending to notational structure rather than computation. I describe an alternative, diagrammatic approach in which pupils do not assess statements but instead use them to make substitutions of notation. I report on two trials of a computer-based task conducted with pairs of pupils and highlight two findings. First, the pupils found it useful to articulate the distinct substitutive effects of commutative (‘swap’, ‘switch’) and partitional (‘split’, ‘separate’) statements when working on the task. Secondly, the pupils did not notice that some of the statements presented were in fact false, which suggests their substituting activities were independent of numerical equivalence conceptions. This demonstrates that making substitutions offers task designers a mathematical utility for equality statements that is distinct from, but complementary to, assessing numerical balance.     

Observing mathematical fluency through students’ oral responses

‘Procedural’ fluency in mathematics is often judged solely on numerical representations. ‘Mathematical’ fluency incorporates explaining and justifying as well as producing correct numerical solutions. To observe mathematical fluency, representations additional to a student’s numerical work should be considered. This paper presents analysis of students’ oral responses. Findings suggested oral responses are important vantage points from which to view fluency – particularly characteristics harder to notice through numerical work such as reasoning. Students’ oral responses were particularly important when students’ written (language) responses were absent/inconsistent. Findings also revealed the importance of everyday language alongside technical terms for observing reasoning as a fluency characteristic. Students used high modality verbs and language features, such as connectives, to explain concepts and justify their thinking. The results of this study purport that to gain a fuller picture of students’ fluency, specifically their explanations or reasoning, students’ oral responses should be analyzed, not simply numerical work.     

Linear representations of formal loops

A representation of an object in a category is an abelian group in the corresponding comma category. In this paper, we derive the formulas describing linear representations of objects in the category of formal loops and formal loop homomorphisms and apply them to obtain a new approach to the representation theory of formal Moufang loops and Malcev algebras based on Moufang elements. Certain ‘non-associative Moufang symmetry’ of groups is revealed.     

Finite dimensional quantum Teichmüller space from the quantum torus at root of unity

Representation theory of the quantum torus Hopf algebra, when the parameter q is a root of unity, is studied. We investigate a decomposition map of the tensor product of two irreducibles into the direct sum of irreducibles, realized as a ‘multiplicity module’ tensored with an irreducible representation. The isomorphism between the two possible decompositions of the triple tensor product yields a map T between the multiplicity modules, called the 6j-symbols. We study the left and right dual representations, and correspondingly, the left and right representations on the Hom spaces of linear maps between representations. Using the isomorphisms of irreducibles to left and right duals, we construct a map A on a multiplicity module, encoding the permutation of the roles of the irreducible representations in the identification of the multiplicity module as the space of intertwiners between representations. We show that T and A satisfy certain consistency relations, forming a Kashaev-type quantization of the Teichmüller spaces of bordered Riemann surfaces. All constructions and proofs in the present work use only plain representation theoretic language with the help of the notions of the left and the right dual and Hom representations, and therefore can be applied easily to other Hopf algebras for future works.     

How Students “Unpack” the Structure of a Word Problem: Graphic Representations and Problem Solving

This research investigated how fourth and fifth grade students spontaneously ‘unpacked’ a word problem when generating a graphic representation to aid in problem solution. Relationships among the type of graphic representation produced, spatial visualization, drawing ability, gender, and problem solving also were examined and described. Instrumentation developed for the study included several math challenge tasks, a spatial visualization task, and a drawing task. For one of the math challenge tasks, students were instructed to draw a picture to assist them with problem solution. These graphic representations generated by students were rated as pictorial or as displaying some level of schematic representation. Schematic representations included germane information from the problem supportive of problem solution. Pictorial representations included expressive and extraneous elements not necessary for problem solution, with no schematic elements. Findings indicated that the majority of students rendered schematic representations, with girls more likely than boys to use schematic representations at a statistically significant level. Students who used schematic visual representations were more successful problem solvers than those pictorially representing problem elements. The more “schematic‐like” the visual representation, the more successful students were at problem solution. Drawing a pictorial representation in the math challenge task also was negatively correlated to drawing skill.     

Galois connexion of a fuzzy subset

By their representation theorem, Negoita and Ralescu ‘identify’ a fuzzy set with a family of ordinary sets (levels). Here we ‘identify’ a fuzzy set with a Galois connexion between the boolean of a set and the valuation set. The two representations are closely connected.     

Moving in and out of contexts in collaborative reasoning about equations

This case study investigates how a group of 12-year-old pupils contextualizes a task formulated as an equation expressed in a word problem. Of special interest is to explore in detail the phenomenon of pupils working with manipulative-based equation-solving methods in a task involving another real world context. The pupils’ small group discussions were videotaped and analyzed in terms of how the pupils contextualized the task in their attempts to arrive at an answer. The results highlight the importance of giving pupils opportunities to realize the particular position of symbolic mathematical representations when dealing with mathematical concepts. While an abstract concept describes something general, concrete representations and specific real-world examples always describe something specific. No one particular example incorporates the rich meaning of an abstract concept. This central distinction needs to be included in teaching practices.     

Geometric and algebraic approaches in the concept of complex numbers

This study explores pupils’ performance and processes in tasks involving equations and inequalities of complex numbers requiring conversions from a geometric representation to an algebraic representation and conversions in the reverse direction, and also in complex numbers problem solving. Data were collected from 95 pupils of the final grade from high schools in Greece (17–18 years old). Results shed light on pupils’ use of two distinct approaches to solve complex number tasks: the geometric and the algebraic approach. The geometric approach was used more frequently, while the pupils used the algebraic approach more consistently and in a more persistent way. The phenomenon of compartmentalization indicating a fragmental understanding of complex numbers was revealed among pupils who implemented the geometric approach. A common phenomenon was pupils’ difficulty in complex number problem solving, irrespective of their preferred type of approach.     

Teachers’ views on dynamically linked multiple representations, pedagogical practices and students’ understanding of mathematics using TI-Nspire in Scottish secondary schools

Do teachers find that the use of dynamically linked multiple representations enhances their students’ relational understanding of the mathematics involved in their lessons and what evidence do they provide to support their findings? Throughout session 2008–2009, this empirical research project involved six Scottish secondary schools, two mathematics teachers from each school and students from different ages and stages. Teachers used TI-Nspire PC software and students the TI-Nspire handheld technology. This technology is specifically designed to allow dynamically linked multiple representations of mathematical concepts such that pupils can observe links between cause and effect in different representations such as dynamic geometry, graphs, lists and spreadsheets. The teachers were convinced that the use of multiple representations of mathematical concepts enhanced their students’ relational understanding of these concepts, provided evidence to support their argument and described changes in their classroom pedagogy.     

The multiplicative meaning conveyed by visual representations

Research and practitioner articles advocate the use of visual representations in scaffolding elementary students’ learning of multiplication and division. Prior research suggests students use different strategies when provided with different visualized representations of multiplication and division. However, there is relatively little study examining how children’s multiplicative reasoning corresponds with different representations. The present study collected data from 182 elementary students responding to set, area, and length representations of multiplication/division. Rasch modeling was used to estimate item difficulty statistics to measure differences between visual representations. Results suggest that visual representations differed primarily in how unit was represented and quantified, and not regarding the form of representation (set, area, length).     

CHILDREN'S PROPORTIONAL REASONING AND TENDENCY FOR AN ADDITIVE STRATEGY: THE ROLE OF MODELS

In this paper we report on 10 –14 year old children's strategies while solving two versions of ratio and proportion tasks: one ‘with models’ thought to facilitate proportional reasoning and one ‘without’. Rasch methodology was used to develop ‘with’ and ‘without models’ test versions which were given to a linked sample involving 673 children. We examine the pupils’ additive errors, their effect on ratio reasoning and how contingent on ‘model’ presentation this is. First, we provide a single scale on which pupils, item-difficulty and additive errors can be located. We then provide a new scale constructed from the error prone items, which we name the ‘tendency for additive strategy’. The measurement data is supported by qualitative data showing that the presence of ‘models’ can sometimes affect children's strategies, both positively and negatively but rarely makes a significant measurement difference on this, untutored, sample.     

The Calculator as a Cognitive Tool: Upper-Primary Pupils Tackling a Realistic Number Problem

This paper examines the idea that the arithmetic calculator can act as a cognitive tool, supporting the amplification or reorganisation of systems of thought. It analyses how a structured sample of pupils in the last year of English primary education, with differing degrees of experience of a ’calculator-aware‘ number curriculum, tackled a realistic number problem, focusing on their use of calculator, written and mental modes of computation. Examples were found in which use of the calculator helped pupils to work with unusual problem representations, and to adopt solution strategies in which they focused on planning and monitoring computations executed by the machine. For most pupils, however, other issues were more salient. First, there was an important dissonance between pupils‘ conception of division and the calculator‘s operationalisation of it, although some cases showed how further experiment or computation with the machine could help to make appropriate connections. Second, while the calculator made it possible to redistribute computation from human to machine, important limitations arose from the transience of the calculator‘s record of operations and results. The observations suggest the importance of developing pupils‘ skill in making effective use of the calculator beyond single, simple computations; and the need to help pupils apprehend the relationship between mathematical concepts and their operationalisation in the machine. This revised version was published online in July 2006 with corrections to the Cover Date.     

Representability in mixed integer programmiing,I: Characterization results

We define the concept of a representation of a set of either linear constraints in bounded integers, or convex constraints in bounded integers. A regularity condition plays a crucial role in the convex case. Then we characterize the representable sets (Theorem 2.1) and provide several examples of our representations.A consequence of our characterization is that the only representable sets are those from ‘either/or’ constraints. This latter case can be treated by generalizations of techniques from the disjunctive methods of cutting-plane theory (e.g. [2] and [30]).The representations given here are intended for use as part of the constraints of a larger optimization problem, where they often can serve to tighten the (linear or convex) relaxation.The study of representations was initiated by Meyer and in the linear case we continue the development in [35].     

Pupils’ attitudes towards mathematics: a comparative study of Norwegian and English secondary students

Comparing English and Norwegian pupils’ attitude towards mathematics, in this article I develop a deeper understanding of the factors that may shape and influence ‘pupil attitude towards mathematics’, and argue for it as a socio-cultural construct embedded in and shaped by students’ environment and context in which they learn mathematics. The theoretical framework leans on work by Zan and Di Martino (The Montana Mathematics Enthusiast, Monograph 3, pp. 157–168, 2007) to elicit Norwegian and English pupils’ attitude of mathematics as they experience it in their respective environments. Whilst there were differences which could be seen to be accounted for by differently ‘figured’ environments, there are also many similarities. It was interesting to see that, albeit based on a small statistical sample, in both countries students had a positive attitude towards mathematics in year 7/8, which dropped in year 9, and increased again in years 10/11. This result could be explained and compared with other larger scale studies (e.g. Hodgen et al. in Proceedings of the British Society for Research into Learning Mathematics. 29(3), 2009). The analysis of pupils’ qualitative comments (and classroom observations) suggested seven factors that appeared to influence pupil attitude most, and these had ‘superficial’ commonalities, but the perceptions that appeared to underpin these mentions were different, and could be linked to the environments of learning mathematics in their respective classrooms. In summary, it is claimed that it is not enough to identify the factors that may shape and influence pupil attitude, but more importantly, to study how these are ‘lived’ by pupils, what meanings are made in classrooms and in different contexts, and how the factors interrelate and can be understood.     

The Interplay Between Gesture and Discourse as Mediating Devices in Collaborative Mathematical Reasoning:A Multimodal Approach

This article aims to identify the mathematical reasoning strategies expressed through gestures and speech used by two groups of sixth-grade pupils when solving a task related to the transition between two semiotic representations: figure and Cartesian diagram. The article also identifies the difficulties the pupils meet in the solution process. The analyses of the group dialogues focus particularly on the gesture dimension of deixis. The pupils in both groups have used the following deictic gestures: pointing, held-point, linear point-slide, and circular point-slide in their solution process, while repeated pointing has been identified only in one of the groups. These pointing gestures are related to the reasoning strategies: comparison of persons in the figure, coordination of two dimensions in the diagram, recapitulation and going to an extreme location. The pupils use the modalities of speech, gesture, and writing in order to solve the mathematical task. Their pointing gestures related to their use of reasoning strategies play a multifaceted role in developing collaborative mathematical reasoning in the two small groups.     

A Modeling Perspective on Interpreting Rates of Change in Context

Functions provide powerful tools for describing change, but research has shown that students find difficulty in using functions to create and interpret models of changing phenomena. In this study, we drew on a models and modeling perspective to design an instructional approach to develop students’ abilities to describe and interpret rates of change in the context of exponential decay. In this article, we elaborate the characteristics of the model development sequence and we examine how students interpreted and described non-constant rates of change in context. We provide evidence for how a focus on the context made visible students’ reasoning about rates of change, including difficulties related to the use of language when describing changes in the negative direction. We argue that context and the use of language, forefronted in a modeling approach, should play an important role in supporting the development of students’ reasoning about changing phenomena.     

Transformations in the Visual Representation of a Figural Pattern

Multiple representations of a given mathematical object/concept are one of the biggest difficulties encountered by students. The aim of this study is to investigate the impact of the use of visual representations in teaching and learning algebra. In this paper, we analyze the transformations from and to visual representations that were performed by 18 students (aged between 10 and 13) in a task designed to explore a figural pattern. The data were collected from an audio recording of the class, the students’ work, and the teacher’s notes about each lesson. The results confirm that visual representations are important. However, visual treatments of any kind of representation are decisive, since they give students other possibilities for seeing and understanding tasks, continuity and flexibility in their activities, and the ability to make conversions between representations. The creative realization of visual treatments is necessary, and the teacher has a significant role in helping students to learn how to do this.     

Students’ multilingual repertoires-in-use for meaning-making: Contrasting case studies in three multilingual constellations

Mathematics education for multilingual classrooms calls for instructional approaches that build upon students’ multilingual resources. However, so far, students’ multilingual resources and the interplay of their components have only partly been disentangled and rarely compared between different multilingual contexts. This article suggests a conceptualization of multilingual repertoires-in-use as characterized by (a) what students use of certain languages, registers, and representations as sources for meaning-making in mathematics classrooms and (b) their processes of how they connect certain languages, registers, and representations. This qualitative learning-process study compares students’ multilingual repertoires-in-use in three contexts: Spanish-speaking foreign language learners of German in Colombia, Turkish- and German-speaking students born in Germany, and Arabic-speaking German language beginners recently immigrated to Germany. The analysis reveals the biggest differences not only in what the students use, but how they connect languages, registers, and representations. Some of these differences can partly be traced back to different classroom cultural practices. These findings suggest extending the conceptual framework for multilingual repertoires-in-use and including it in a social theoretical perspective. Thus, these findings have important practical consequences for multilingual mathematics classrooms: The instructional approach of relating languages, registers, and representations needs to be applied more flexibly, taking into account students’ different starting points. When doing so, students’ connection processes should be supported and explicated more systematically in order to fully exploit the students’ repertoires.