MAKING LINKS BETWEEN ARITHMETIC AND ALGEBRAIC THINKING

In the Purposeful Algebraic Activity project we have designed and implemented a series of six spreadsheet based tasks for year 7 pupils aimed at developing early algebraic competence. Our data collection and analysis have been designed to collect evidence about specific features of both the spreadsheet environment and of task design, which influence the ways in which pupils engage with the notion of variable. In this paper we present a case study of one pair of pupils using data from the teaching programme and interviews. We use this case study to identify elements of the task design which have influenced the development of the pupils' thinking.     

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.     

METAPHORS AND OTHER LINGUISTIC POINTERS TO CHILDREN'S MENTAL REPRESENTATIONS

The mental representations that 6- and 7-year-old pupils form as a result of their interactions with their teacher's verbal, written, pictorial and concrete material representations has to be inferred from the language they use. In this study many pupils seem to have mental representations which capture surface characteristics of a particular teachers’ representation and use metaphoric language associated with that representation when describing their calculations. Pupils’ use of ‘you’ is characteristic of those who adopt a representation-specific procedure, whilst ‘if’ and ‘like’ are linguistic pointers to their use of generic examples to describe a procedure. Individual pupils show a preference for the same style of mental representation when describing images and procedures in mathematical and non-mathematical contexts.     

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.     

An “Instrumental Approach” to Study the Integration of a Computer Tool Into Mathematics Teaching: the Case of Spreadsheets

This article reports on research focused on the integration of a specific computer tool, the spreadsheet, into mathematics teaching. After presenting some important results obtained by research in this area, we revisit these in the light of an instrumental approach, which we perceive as essential to analyse the construction of mathematical meanings in spreadsheet environments and to understand better the questions of technological integration. Then, these theoretical elements are used in order to design an exploratory experiment with grade 7 pupils and analyse its results.     

Assigning pupils to tutor groups in a comprehensive school

Comprehensive schools in the UK have the annual task of assigning their intake of new pupils to tutor groups. This case study describes how the problem has been addressed at one such school, where several factors are taken into account in order to make the groups as similar as possible and, since pupils have an induction day in June when they assemble in their tutor groups and meet their new tutors, where the time scale is short. Manual allocation has been used in the past, needing many staff-hours to achieve a satisfactory result. Heuristics implemented on a spreadsheet have enabled substantial savings in staff time and given more evenly balanced tutor groups.     

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.     

Purposeful contexts for formal notation in a spreadsheet environment

This article addresses the early stages of children's introduction to the use of variables in formal algebraic notation. We conjecture that some of the difficulties encountered by children in this area may be accentuated by their lack of appreciation of the purpose or power of formal notation. A teaching approach is described that aims to situate the use of formal notation in meaningful contexts. A study of a teaching sequence based on children working with this approach, using graphical feedback in problem solutions, is presented.     

Coding strategic behaviour in mathematical problem solving

There has been some debate about the extent to which contextual'stories' and graphical images can help pupils to think their way through numerical problems. The degree to which contexts stimulate useful'models to think with' may vary considerably. Some contexts seem to encourage children to reason more effectively, but others have little impact either on pupils'performance, or on the way in which they tackle the computations required. In this study three sets of four questions involving subtraction and division were trialled with a total sample of 1795 Year 6 to 9 pupils. In each comparison, about a quarter of the pupils could answer the question only when it was presented in context, or only out of context, but not both. Pupils' methods of working were analysed to reveal differences in their approach to the different questions.     

FROM ONE LANGUAGE TO ANOTHER: A SEMIOTIC INTERPRETATION OF THE TRANSLATION OF MATHEMATICAL WORDS

The teaching and learning of Primary school mathematics in Malta involves the use of code-switching between the local language Maltese, and English Mathematical terms themselves are usually retained in English and teachers may use various strategies to share the meaning of these words with their pupils. One strategy that may be used in a bilingual situation is translation from one language to another. In this paper I explore how a teacher used this strategy to teach her 7 to 8-year-old pupils mathematical vocabulary related to the topic'Money and Shopping'. While Maltese equivalents for these words exist, it is the English versions that form part of the school mathematics register. I develop a semiotic model where a mathematical word is considered to be a sign, and the process of translation is viewed as a chain of signification from one language to another.     

A Symbolic Dance: The Interplay Between Movement,Notation, and Mathematics on a Journey Toward Solving Equations

This article analyzes the use of the software Grid Algebra with a mixed ability class of 21 nine-to-ten-year-old students who worked with complex formal notation involving all four arithmetic operations. Unlike many other models to support learning, Grid Algebra has formal notation ever present and allows students to “look through” that notation and interpret it either in terms of physical journeys on a grid or in terms of mathematical operations. A dynamic fluidity was found between the formal notation, imagery of movements on a grid, and the process of mathematical operations. This fluidity is interpreted as a “dance” between these three. The significant way in which this dynamic took place reflects the scaffolding and fading offered by the software, which was crucial to the students’ fluency with formal notation well beyond what has been reported from students of that age.     

Acquiring new use of multiplication through classroom teaching: an exploratory study

This article analyzes the process in which pupils acquire new uses of multiplication to measure area. Behaviors of five 4th-grade pupils in a series of lessons on areas were studied in depth by qualitative case-study methodology. Their use of multiplication changed as the lesson evolved, characterized conceptually as “using multiplication as a label,” “using it positively to approach problems which have not been solved before,” and “using it effectively to achieve the goal of measuring areas.” These three phases show the pupils’ understanding of multiplication in the context of measuring areas from a secondary accompaniment to a powerful tool of thinking. The phases observed and the students’ progress between the phases differs noticeably among the pupils. Factors that foster learners’ progress are investigated by comparing their behaviors.     

Fractions as Subtraction: An Activity‐Oriented Perspective from Elementary Children

A sample of third‐, fourth‐, and fifth‐grade student responses to the question “What is a fraction?” were examined to gain an understanding of how children in upper elementary grades make sense of fractions. Rather than measure children's understanding of fractions relative to mathematically conventional part–whole constructions of fractions, we attempted to understand children's actions and processes. A small but nontrivial group of children used subtraction (takeaway and removal) as a framework for understanding how fractions were created and written. An analysis of the content of their responses as well as a comparison of the performance of these children with that of children who used other ways of describing fractions suggests that the use of subtraction may be a reasonable (or at least not harmful) way for children to begin to access concepts related to fractions. Also, this study suggests that attention to children's understanding through the lens of children's activity might reveal ways of thinking and insights that are masked when we compare children's thinking in more structured research settings.     

A simplified functorial construction of the veblen hierarchy

We give a simple and elementary proof of the following result of Girard and Vauzeilles which is proved in [5]: “The binary Veblen function ψ: On × On — On is a dilator.” Our proof indicates the intimate connection between the traditional theory of ordinal notation systems and Girard's theory of denotation systems. MSC: 03F15.     

On access to temporary resources

The shareable resources of a multiprogramming system can be classified as either permanent or temporary, and their use can be classified as either exclusive or non-exclusive. While semaphores, as defined by Dijkstra synchronize access to permanent resources, this article proposes two new primitives for synchronizing access to temporary resources. Their usefulness is demonstrated by examining the problem of a number of concurrent «readers» and »writers« sharing a single file. Finally, a high-level language notation is proposed which synchronizes access to a declared, shareable resource of any of the categories classified above.     

Helping students build a path of understanding from ratio and proportion to decimal notation

Various studies have shown that students of all levels struggle to understand decimal numbers. This paper discusses a novel approach to increasing students’ conceptual understanding of decimal numbers. Rather than approach decimal notation as a discrete and separate mathematical topic, this approach enables students to work with contextual problems to gain a solid understanding of ratio and proportion. Using their understanding of ratio and proportion as a foundation, students can then build connected and related understandings of fractions, decimals and percents. The study discussed in this paper illustrates that grounding decimal instruction in the broader context of ratio can help students gain deeper conceptual understandings of decimal notation as well as fractions and percents.     

Charting Northern Skies With the Aid of a Spreadsheet

An obstacle often encountered in preparing for an astronomical viewing evening is the difficulty of locating appropriate and easy-to-use star charts. This article describes, briefly, two types of star charts commonly available. Both are less than ideal for use by school students because of their complexity or lack of direct applicability to the observer's location. A strategy is outlined by which teachers can have students prepare, using a computer spreadsheet, their own easy-to-use star charts which are appropriate for the location, date, and time of viewing.     

Using Sociocultural Theory to Teach Mathematics: A Vygotskian Perspective

This study describes an elementary teacher's implementation of sociocultural theory in practice. Communication is central to teaching with a sociocultural approach and to the understanding of students; teachers who use this theory involve students in explaining and justifying their thinking. In this study ethnographic research methods were used to collect data for 4 1/2 months in order to understand the mathematical culture of this fourth‐grade class and to portray how the teacher used a sociocultural approach to teach mathematics. To portray this teaching approach, teaching episodes from the teacher's mathematics lessons are described, and these episodes are analyzed to demonstrate how students created taken‐as‐shared meanings of mathematics. Excerpts from interviews with the teacher are also used to describe this teacher's thinking about her teaching.     

Interactive Optimization Aspects of Electronic Spreadsheet Models for Design and Planning

This paper extends the discussion of the relationship between optimization and electronic spreadsheet modelling. Previous authors have described two connections. These are, first, the use of spreadsheets to facilitate optimization projects and, second, the use of optimization within the spreadsheet model itself such as for cell value computation. In this paper we argue that use of the spreadsheet model for planning and design problems often may actually be viewed as interactive multi-criterion optimization per se. This provides a third connection between optimization and spreadsheet models. We base our arguments on a simplified example arising in insurance consulting work and note other examples as well. We also propose a method for incorporating this observation into existing spreadsheet models and indicate desirable innovations in spreadsheet software.