Mathematical Sciences Education Board

Center for Science, Mathematics, and Engineering Education

National Research Council

 






5

Working with Algebra


Daniel Chazan
Michigan State University

Sandra Callis Bethell
Holt High School



Teaching a mathematics class in which few of the students have demonstrated success is a difficult assignment. Many teachers avoid such assignments, when possible. On the one hand, high school mathematics teachers, like Bertrand Russell, might love mathematics and believe something like the following:

Mathematics, rightly viewed, possesses not only truth, but supreme beauty--a beauty cold and austere, like that of sculpture, without appeal to any part of our weaker nature, without the gorgeous trappings of painting or music, yet sublimely pure, and capable of a stern perfection such as only the greatest art can show. . . . Remote from human passions, remote even from the pitiful facts of nature, the generations have gradually created an ordered cosmos, where pure thought can dwell as in its nature home, and where one, at least, of our nobler impulses can escape from the dreary exile of the natural world. (Russell, 1910, p. 73)

     But, on the other hand, students may not have the luxury, in their circumstances, of appreciating this beauty. Many of them may not see themselves as thinkers because contemplation would take them away from their primary focus: how to get by in a world that was not created for them. Instead, like Jamaica Kincaid, they may be asking:

What makes the world turn against me and all who look like me? I won nothing, I survey nothing, when I ask this question, the luxury of an answer that will fill volumes does not stretch out before me. When I ask this question, my voice is filled with despair. (Kincaid, 1996, pp. 131-132)



Our Teaching and Issues It Raised


     During the 1991-92 and 1992-93 school years, we (a high school teacher and a university teacher educator) team taught a lower track Algebra I class for 10th through 12th grade students.1 Most of our students had failed mathematics before, and many needed to pass Algebra I in order to complete their high school mathematics requirement for graduation. For our students, mathematics had become a charged subject; it carried a heavy burden of negative experiences. Many of our students were convinced that neither they nor their peers could be successful in mathematics.

     Few of our students did well in other academic subjects, and few were headed on to two- or four-year colleges. But the students differed in their affiliation with the high school. Some, called "preppies" or "jocks" by others, were active participants in the school's activities. Others, "smokers" or "stoners," were rebelling to differing degrees against school and more broadly against society. There were strong tensions between members of these groups.2

     Teaching in this setting gives added importance and urgency to the typical questions of curriculum and motivation common to most algebra classes. In our teaching, we explored questions such as the following:

  • What is it that we really want high school students, especially those who are not college-intending, to study in algebra and why?

  • What is the role of algebra's manipulative skills in a world with graphing calculators and computers? How do the manipulative skills taught in the traditional curriculum give students a new perspective on, and insight into, our world?

  • If our teaching efforts depend on students' investment in learning, on what grounds can we appeal to them, implicitly or explicitly, for energy and effort? In a tracked, compulsory setting, how can we help students, with broad interests and talents and many of whom are not college-intending, see value in a shared exploration of algebra?



An Approach to School Algebra


     As a result of thinking about these questions, in our teaching we wanted to avoid being in the position of exhorting students to appreciate the beauty or utility of algebra. Our students were frankly skeptical of arguments based on utility. They saw few people in their community using algebra. We had also lost faith in the power of extrinsic rewards and punishments, like failing grades. Many of our students were skeptical of the power of the high school diploma to alter fundamentally their life circumstances. We wanted students to find the mathematical objects we were discussing in the world around them and thus learn to value the perspective that this mathematics might give them on their world.

     To help us in this task, we found it useful to take what we call a "relationships between quantities" approach to school algebra. In this approach, the fundamental mathematical objects of study in school algebra are functions that can be represented by inputs and outputs listed in tables or sketched or plotted on graphs, as well as calculation procedures that can be written with algebraic symbols.3 Stimulated, in part, by the following quote from August Comte, we viewed these functions as mathematical representations of theories people have developed for explaining relationships between quantities.

In the light of previous experience, we must acknowledge the impossibility of determining, by direct measurement, most of the heights and distances we should like to know. It is this general fact which makes the science of mathematics necessary. For in renouncing the hope, in almost every case, of measuring great heights or distances directly, the human mind has had to attempt to determine them indirectly, and it is thus that philosophers were led to invent mathematics. (Quoted in Serres, 1982, p. 85)



The "Sponsor" Project


     Using this approach to the concept of function, during the 1992-93 school year, we designed a year-long project for our students. The project asked pairs of students to find the mathematical objects we were studying in the workplace of a community sponsor. Students visited the sponsor's workplace four times during the year--three after-school visits and one day-long excused absence from school. In these visits, the students came to know the workplace and learned about the sponsor's work. We then asked students to write a report describing the sponsor's workplace and answering questions about the nature of the mathematical activity embedded in the workplace. The questions are organized in Table 5-1.



Table 5-1: Questions to ask in the workplace

 
Quantities: Measured or counted versus computed
  • What quantities are measured or counted by the people you interview?
  • What kinds of tools are used to measure or count?
  • Why is it important to measure or count these quantities?
  • What quantities do they compute or calculate?
  • What kinds of tools are used to do the computing?
  • Why is it important to compute these quantities?
  • Computing quantities
  • When a quantity is computed, what information is needed and then what computations are done to get the desired result?
  • Are there ever different ways to compute the same thing?
  • Representing quantities and relationships between quantities
  • How are quantities kept track of or represented in this line of work?
  • Collect examples of graphs, charts, tables, etc. that are used in the business.
  • How is information presented to clients or to others who work in the business?
  • Comparisons
  • What kinds of comparisons are made with computed quantities?
  • Why are these comparisons important to do?
  • What set of actions are set into motion as a result of interpretation of the computations?
  •  




    Using These Questions


         In order to determine how the interviews could be structured and to provide students with a model, we chose to interview Sandra's husband, John Bethell, who is a coatings inspector for an engineering firm. When asked about his job, John responded, "I argue for a living." He went on to describe his daily work inspecting contractors painting water towers. Since most municipalities contract with the lowest bidder when a water tower needs to be painted, they will often hire an engineering firm to make sure that the contractor works according to specification. Since the contractor has made a low bid, there are strong financial incentives for the contractor to compromise on quality in order to make a profit.

         In his work John does different kinds of inspections. For example, he has a magnetic instrument to check the thickness of the paint once it has been applied to the tower. When it gives a "thin" reading, contractors often question the technology. To argue for the reading, John uses the surface area of the tank, the number of paint cans used, the volume of paint in the can, and an understanding of the percentage of this volume that evaporates to calculate the average thickness of the dry coating. Other examples from his workplace involve the use of tables and measuring instruments of different kinds.



    Some Examples of Students' Work


         When school started, students began working on their projects. Although many of the sponsors initially indicated that there were no mathematical dimensions to their work, students often were able to show sponsors places where the mathematics we were studying was to be found. For example, Jackie worked with a crop and soil scientist. She was intrigued by the way in which measurement of weight is used to count seeds. First, her sponsor would weigh a test batch of 100 seeds to generate a benchmark weight. Then, instead of counting a large number of seeds, the scientist would weigh an amount of seeds and compute the number of seeds such a weight would contain.

         Rebecca worked with a carpeting contractor who, in estimating costs, read the dimensions of rectangular rooms off an architect's blueprint, multiplied to find the area of the room in square feet (doing conversions where necessary), then multiplied by a cost per square foot (which depended on the type of carpet) to compute the cost of the carpet. The purpose of these estimates was to prepare a bid for the architect where the bid had to be as low as possible without making the job unprofitable. Rebecca used a chart (Table 5-2) to explain this procedure to the class.



    Table 5-2: Cost of carpet worksheet

     
    Inputs Output
    Length Width Area of the Room Cost for Carpeting Room
    10 35    
    20 25    
    15 30    
     


         Joe and Mick, also working in construction, found out that in laying pipes, there is a "one by one" rule of thumb. When digging a trench for the placement of the pipe, the non-parallel sides of the trapezoidal cross section must have a slope of 1 foot down for every one foot across. This ratio guarantees that the dirt in the hole will not slide down on itself. Thus, if at the bottom of the hole, the trapezoid must have a certain width in order to fit the pipe, then on ground level the hole must be this width plus twice the depth of the hole. Knowing in advance how wide the hole must be avoids lengthy and costly trial and error.

         Other students found that functions were often embedded in cultural artifacts found in the workplace. For example, a student who visited a doctor's office brought in an instrument for predicting the due dates of pregnant women, as well as providing information about average fetal weight and length (Figure 5-1).



    Figure 5-1:
    Pregnancy wheel

       
      Source: Matria Healthcare, Marietta, GA.




    Conclusion


         While the complexities of organizing this sort of project should not be minimized--arranging sponsors, securing parental permission, and meeting administrators and parent concerns about the requirement of off-campus, after-school work--we remain intrigued by the potential of such projects for helping students see mathematics in the world around them. The notions of identifying central mathematical objects for a course and then developing ways of identifying those objects in students' experience seems like an important alternative to the use of application-based materials written by developers whose lives and social worlds may be quite different from those of students.



    References


      Chazen, D. (1996).
      Algebra for all students? Journal of Mathematical Behavior, 15(4), 455-477.

      Eckert, P. (1989).
      Jocks and burnouts: Social categories and identity in the high school. New York: Teachers College Press.

      Fey, J. T., Heid, M. K., et al. (1995).
      Concepts in algebra: A technological approach. Dedham, MA: Janson Publications.

      Kieran, C., Boileau, A., & Garancon, M. (1996).
      Introducing algebra by means of a technology-supported, functional approach. In N. Bednarz et al. (Eds.), Approaches to algebra, (pp. 257-293). Kluwer Academic Publishers: Dordrecht, The Netherlands.

      Kincaid, J. (1996).
      The autobiography of my mother. New York: Farrar, Straus, Giroux.

      Nemirovsky, R. (1996).
      Mathematical narratives, modeling and algebra. In N. Bednarz et al. (Eds.) Approaches to algebra, (pp. 197-220). Kluwer Academic Publishers: Dordrecht, The Netherlands.

      Russell, B. (1910).
      Philosophical Essays. London: Longmans, Green.

      Schwartz, J. & Yerushalmy, M. (1992).
      Getting students to function in and with algebra. In G. Harel & E. Dubinsky (Eds.), The concept of function: Aspects of epistemology and pedagogy, (MAA Notes, Vol. 25, pp. 261-289). Washington, DC: Mathematical Association of America.

      Serres, M. (1982).
      Mathematics and philosophy: What Thales saw . . . In J. Harari & D. Bell (Eds.), Hermes: Literature, science, philosophy, (pp. 84-97). Baltimore, MD: Johns Hopkins.

      Thompson, P. (1993).
      Quantitative reasoning, complexity, and additive structures. Educational Studies in Mathematics, 25, 165-208.

      Yerushalmy, M. & Schwartz, J. L. (1993).
      Seizing the opportunity to make algebra mathematically and pedagogically interesting. In T. A. Romberg, E. Fennema, & T. P. Carpenter (Eds.), Integrating research on the graphical representation of functions, (pp. 41-68). Hillsdale, NJ: Lawrence Erlbaum Associates.



    Notes


    1 For other details, see Chazan (1996).

    2 For more detail on high school students' social groups, see Eckert (1989).

    3 Our ideas have been greatly influenced by Schwartz & Yerushalmy (1992) and Yerushalmy & Schwartz (1993) and are in the same spirit as the approach taken by Fey, Heid, et al. (1995), Kieran, Boileau, & Garancon (1996), Nemirovsky (1996), and Thompson (1993).




      Daniel Chazan is an Associate Professor of Teacher Education at Michigan State University. To assist his research in mathematics teaching and learning, he has taught algebra at the high school level. His interests include teaching mathematics by examining student ideas, using computers to support student exploration, and the potential for the history and philosophy of mathematics to inform teaching.


      Sandra Callis Bethell has taught mathematics and Spanish at Holt High School for 10 years. She has also completed graduate work at Michigan State University and Western Michigan University. She has interest in mathematics reform, particularly in meeting the needs of diverse learners in algebra courses.




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