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1994 Book DidacticsOfMathematicsAsAScien
instructions to generate sequences as illustrated by the following example:
Follow the instructions to find all the square numbers between 0 and 100 179 FOR NUMBER = 1 TO 10 PRINT NUMBER * NUMBER NEXT NUMBER END 10 20 30 40 In the strand related to problem-solving, it states that students are expected to identify and obtain information necessary to solve problems. This is elab- orated as: When trying to draw repeating patterns of different sizes using Logo, realize the need for a procedure to incorporate a variable, and request and interpret instructions for doing it. The whole nature of this UK National Curriculum is such that it frag- ments mathematics, and, as can be seen from the above example, ideas from computer programming have become so fragmented as to be almost point- less. But computer programming in schools predates the National Curriculum, and I am optimistic enough to believe that some of the absurdi- ties in this new curriculum will change with time. Over the last 10 years, computer provision in schools has changed dramatically. Ten years ago, we had to provide the computers in order to carry out our research in the class- room. Nowadays, we can easily find schools with adequate computer pro- vision. The school in which I recently completed a project has three com- puter rooms full of networked computers and a computer in each mathemat- ics classroom. Many secondary schools in the UK now have good computer facilities, but the mathematics teachers still need considerable support to For a number of years I have been working on the ways in which pro- gramming influences students' developing use and understanding of alge- braic ideas. This work was initially influenced by the considerable research on students' learning of algebra (e.g., Küchemann, 1981), which reported that students find it difficult to understand that a letter in algebra can repre- sent a range of numbers and to accept “unclosed" expressions in algebra (e.g., x + 4). Most of this work on childrens’ understanding of algebra was influenced by a Piagetian perspective. The implicit assumption often made was that if students cannot perform satisfactorily on certain algebraic tasks, then they have not reached the stage of formal operations. Results from work in computer programming environments conflict with many of the es- tablished results on the learning of traditional algebra (Sutherland, 1992; Tall, 1989) 180 THE ROLE OF PROGRAMMING make use of these facilities for teaching and learning mathematics (Sutherland, Hoyles, & Noss, 1990). 3. COMPUTER PROGRAMMING AND LEARNING ALGEBRA 4. LOGO PROGRAMMING Our first study carried out with the programming language Logo (Sutherland, 1989) as part of the Logo Maths Project (Hoyles & Sutherland, 1989) showed that, with Logo programming experience, students develop a different view of literal symbols from those developed within school alge- bra. Tall also found similar results working with the BASIC programming language (Tall, 1989). In the programming environment, students know that any name can be used for a variable, that a variable name (either a word or a literal symbol) represents a range of numbers, and readily accept the idea of working with unclosed, variable-dependent expressions. Moreover, many students can use these programming experiences and more traditional alge- bra situations (Sutherland, in press). But the most important result from this work, which influenced the direction of our ongoing research, was that the algebra understandings that students develop depend very much on the na- ture of their Logo programming experiences, and this is influenced by the way the teacher structures the classroom situation. In retrospect, this seems like common sense, but, at the time, the prevalent theoretical view, influ- enced by the theories of Piaget, was that algebraic understandings depend more on the developmental stage of the child. Initially in the Logo Maths Project, we had been cautious about introducing the idea of variable to stu- dents because of an awareness of the negative attitudes many students have about algebra. So, in the first instance, we waited for students to choose goals that needed the idea of variable, and only changed this strategy when it became clear that most of them would not do this spontaneously. The de- velopment in our teaching approach and how it changed within two subse- quent projects has been described in Sutherland (1993). When a whole class of students are working on computer programming activities, they can be actively engaged in their own process of problem- solving. The teacher's role ought to be one of providing problems to be solved, or letting students choose their own problem, giving support with syntax, discussing a problem solution, but essentially devolving much of the responsibility to the students themselves. It seems that the crucial factor here, from the point of view of mathematics education, is that the students construct a problem solution themselves. This contrasts with the idea of giv- ing students a preprogrammed algorithm, which is more prevalent in the teaching of BASIC than in the teaching of Logo. Presenting students with standard solutions is also part of school mathematics practice, and Mason (1993) has criticized the fact that, in much of school algebra, students are presented with someone else's solution to a problem and are not given the opportunity to construct their own solutions. Interactive programming lan- guages provide an ideal setting for students to construct their own programs, so it is interesting to question why teachers so often provide programming solutions for their students, either in the form of pre-written macros or standard algorithms. It may result from a lack of confidence, on the part of the teacher, that students will be able to construct their own programs – often a projection of the teacher's own lack of confidence and expertise onto the students. Another reason relates to the "mainframe mentality" and the idea that a program solution must be planned away from the computer. ROSAMUND SUTHERLAND 181 5. A SPREADSHEET ENVIRONMENT – EXCEL More recently, I have been working with the spreadsheet Excel with groups of 10-year-olds, 11- to 13-year-olds and 14- to 15-year-olds. Here I will dis- cuss the work with the older group of students who were chosen because they had all experienced considerable difficulty with school mathematics – many of them were disaffected with mathematics and disaffected with school, and all of them had very little previous experience of algebra. All students were interviewed at the beginning and end of the study in order to trace their developing use of algebraic ideas. The majority of the 14- to 15- year-olds could not answer any of the pre-interview questions that focused on the algebraic ideas of: expressing generality; symbolizing a general rela- tionship; interpreting symbolic expressions; expressing and manipulating the unknown; function and inverse function. All of the students had great difficulty in expressing very simple general rules in natural language (e.g., “add 3”), and none of them were able to answer questions on inverse func- tions. The majority were unfamiliar with literal symbols exhibiting the clas- sic “misconceptions” reported in a number of algebra studies (e.g., Küchemann, 1981). For example, Jo thought that the higher the position in the alphabet the larger the number represented. This clearly related to expe- 182 THE ROLE OF PROGRAMMING riences from primary school: “A starts off as one or something . . . when we Download 5.72 Mb. Do'stlaringiz bilan baham: |
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