Enhancing Reasoning Attitudes Of Prospective Elementary School Mathematics Teachers
Transcript of Enhancing Reasoning Attitudes Of Prospective Elementary School Mathematics Teachers
DVORA PERETZ
ENHANCING REASONING ATTITUDES OF PROSPECTIVE
ELEMENTARY SCHOOL MATHEMATICS TEACHERS
ABSTRACT. This article presents a constructivist approach for teaching mathematics
to prospective elementary school teachers in USA. This approach employs a model of a
‘‘mathematical situation,’’ a set of physical operations and a physical language to
reason about students’ mathematical doings. One of the primary goals of this approach
is to promote a reasoning attitude toward the learning of mathematics by prospective
elementary school teachers. At the same time this approach encourages the develop-
ment of their reasoning skills. This approach provides a less rigid frame for discussing
mathematics ‘‘doings’’, [The word ‘‘doings’’ in this manuscript refers to the variety of
mathematical activities, from thinking on a mathematical problem, using manipula-
tives, graphing, solving and so forth.] which is still structured enough to allow
prospective teachers to appreciate the kinds of doings and argumentations found in
mathematics. It provides a concrete-like basis that serves to promote the understanding
of arithmetical concepts (especially fractions). In the context of teacher education, this
approach adds structure and content to the usual curriculum of basic mathematics
courses for future elementary and middle school teachers. It grants future teachers a
higher degree of flexibility in dealing with their students’ questions and learning
difficulties.
KEY WORDS: reasoning, attitudes, mathematics teachers’ education
INTRODUCTION
Most, if not all, prospective elementary school teachers in their first
semester in college would offer, if asked, various reasons for
‘‘why’’ 3� 12 ¼ 6: Among these: ‘‘because this is the way it is done,’’
‘‘my teacher said so’’ or ‘‘flip the guy and multiply.’’1 Dreyfus and
Hadas (1996) argue that proof is an answer to the question ‘‘why;’’
certainly they would not consider this ‘‘individualized’’ kind of reason-
ing a proof, though all of these responses are indeed answers to the
question ‘‘why.’’ These answers explain why the individual student
gave six as an answer and not why six is the mathematically correct
Journal of Mathematics Teacher Education (2006) 9:381–400 � Springer 2006
DOI 10.1007/s10857-006-9013-9
answer to the mathematical challenge. This line of reasoning has no
bearing on the specific situation at hand. In the above mathematical
challenge it could easily support a 2 and 16 as correct answers in the
same manner: 3� 12 ¼ 3þ1
2 ¼ 2 is true because ‘‘this is the way it is
done,’’ and 3� 12 ¼ 1
3� 12 ¼ 1
6 is true because ‘‘flip the guy and multi-
ply.’’ It is as if an external authority required the students to accept
the arguments as true.
Improving the reasoning of prospective teachers, especially in the
context of science and mathematics, is not only a question of ‘‘teach-
ing’’ reasoning in some agreed manner, but also of changing attitudes.
The latter is a much harder task and it is one of utmost importance.
There is a need to promote the urge for a reasonable reason within
our students. How do we make them start asking ‘‘why?’’ How can we
make them appreciate the need to reason about their mathematical
‘‘doings?’’
This article describes a constructivist approach Teaching–Learning–
Space (TLS) that I have employed in order to get my undergraduate
elementary school prospective teachers students to unpack their fragile
mathematical assets and to re-construct a deeper and more flexible
understanding of the basic mathematical concepts, which for the most
part they already ‘‘know.’’ The main goals of this approach are to
encourage them to understand their mathematical ‘‘doings’’ and to
promote a reasoning attitude within them, rather than just teaching
them the basic arithmetical concepts. This approach focuses on the
teaching of arithmetic as a whole, not just on the teaching of frac-
tions. Having said that, some of the applications that I found most
powerful, and a few which I cite here, do deal with fractions.
As in any teaching approach, the TLS encompasses different
aspects underlying different teaching outcomes. The modeling aspects
of the TLS are discussed in Peretz (2005); it is a formalization of the
proposed approach as an Inverse Mathematical Model. Other aspects,
such as issues of language and of teaching for understanding, are the
focus of other papers currently under preparation. In this paper, I
show how the TLS approach can be used by teachers as a tool to
advance students’ mathematical reasoning.
Thus, the conceptual framework presented is applicable to the field
of reasoning in mathematics education and supports those aspects per-
taining to issues of reasoning in the context of a constructivist teach-
ing approach. A brief overview of the approach is provided, followed
by a description of the approach vis-a-vis a class engagement. The
theoretical attributes of the proposed approach will be discussed in the
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context of a few examples of its applications. The insights reported in
the concluding section are based on my observations as the teacher of
the class and offer the reader a sense of the class at the end of the
semester. The discussion highlights some of the key aspects of the TLS
approach and refers briefly to the possibility of employing it in
elementary school.
CONCEPTUAL FRAMEWORK
Promoting reasoning skills of students is treated extensively in the
literature. This article contends that students first need to feel the
‘‘need’’ to reason; they need to develop a reasoning attitude, or a rea-
soning habit of mind. Otherwise, teaching them reasoning skills, the
‘‘how’’ to reason, is algorithmic, or as Selden and Selden (1995) say,
ritualistic. They call for building an early experiential base for the
concept of proof as they claim that:
Both weak validation skills and viewing proofs as ritualistic, and unrelated to
common sense reasoning, may be partially traceable to the absence of arguments,especially student-produced arguments, in school mathematics (p. 141).
The kind of reasoning to employ depends on the specific field-context
and on the specific level of formality required (e.g., the traditional two-
columns (claim–reason) vs. sketches in geometry or epsilon–delta in
calculus). Offering prospective teachers many opportunities to exercise
self-produced argumentation in contexts which differ in their level of for-
mality might serve not only to build an experiential base for the concept
of proof within the prospective teachers themselves, but also to suggest
ways in which they might encourage their future students to build an ear-
ly experiential base for the concept of proof as Selden and Selden (1995)
recommend.
Fischbein and Kedem (1982) describe the confusion of students in
the context of proof and evidence. It seems that some students are
willing to accept proofs as valid, but still prefer to strengthen their
conviction by additional empirical evidence. This might be linked to
Hersh’s (1993) observation:
mathematical proof can convince, and it can explain. In mathematics research, its
primary role is convincing. At the high-school or undergraduate level, its primaryrole is explaining (p.398).
Strengthening the links between ‘‘empirical’’ evidence and
‘‘accepted’’ proof might not only carry explanatory power for the
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student, but might also clear up some of the confusion that Fischbein
and Kedem (1982) discuss.
In Show How You Know: A Visual Medium for Demonstrative
Discourse, the authors Moore and Schwartz (1994) describe an effort
to create a mathematics learning environment in which the social
nature of the classroom facilitates conceptual conjecture and justifica-
tion. A visual representation is designed which students can manipu-
late to obtain demonstrative proofs. They describe how students began
to create a culture in which demonstration became a social phenome-
non. Such a social climate in a class of young students or of prospec-
tive teachers might contribute to the development of a sense of the
need to reason about any given mathematical situation, which in turn
might promote a reasoning attitude.
Moore and Schwartz contend that ‘‘to prove’’ is to ‘‘show’’ that
your statement is ‘‘true.’’ One way of doing this is to bring sufficient
‘‘adequate’’ reasons to convince everyone in your community. Another
way is simply to ‘‘show’’ that it works. For example, to prove the
Graham–Schmidt theorem, which asserts the existence of an orthogo-
nal basis in a finite dimension inner product space,2 one ‘‘builds’’ an
ortho-normal basis from scratch – it is as if one just provides the
required basis, which not only proves its existence, but also suggests a
constructive algorithm for finding such a basis in any given situation.
From here, we see that answering the right ‘‘whys,’’ i.e., why is a
mathematical statement true/not true constitutes a proof. Mathemati-
cal proofs or mathematical lines of reasoning differ from each other in
the context in which they are performed and in the level of their for-
mality. To prove that 2 + 3 = 5 one might use concrete blocks or
one could turn to set theory, use sets of appropriate sizes and refer to
the definition of binary operations on sets, such as union. We treat
both proofs as appropriate in different contexts: set theory might be
appropriate for an undergraduate while concrete blocks might be
appropriate for elementary school students. I would not expect pro-
spective elementary teachers to use set theory rigorously, yet I believe
they would benefit from knowing the relevant concepts from set
theory and the ways in which they are related to the arithmetic
operations, as it is done in the TLS approach.
What might a constructivist perspective imply for teaching mathe-
matics to prospective elementary school teachers? Guided inquiries,
explorations, evaluative reflections promote the construction of under-
standing in both individual and social contexts. Interpretative dis-
course allows variety of interpretation and leads to negotiation and
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agreement rather than to the ‘‘right solution’’ or the ‘‘right method,’’
and ‘‘The pedagogical structure for learning [...] is shared by the
learner and the teacher’’ (Yore, 2001).
Richards (1991) describes how a teacher might go about thinking
about a constructivist teaching approach that is relevant for the
proposed TLS approach:
It is necessary to provide a structure and a set of plans that support the develop-
ment of informed exploration and reflective inquiry without taking initiative orcontrol away from the student. The teacher must design tasks and projects thatstimulate students to ask questions, pose problems, and set goals. Students will
not become active learners by accident, but by design, through the use of the plansthat we structure to guide exploration and inquiry (p. 38).
Next, I present the Teaching–Learning–Space (TLS) approach,
which promotes the urge to reason by: (1) Making it a habit to ask
the right ‘‘why;’’ (2) Having the students reason in different contexts,
(3) Involving the students in a mathematical-like discourse that is less
formal than the traditional mathematical discourse, yet maintains a
certain level of rigor, and (4) Reconstructing an intuitive basis for the
learning of mathematics.
THE TEACHING–LEARNING–SPACE APPROACH
The Teaching–Learning–Space (TLS) is a teaching model for teaching
arithmetic-based mathematics. I developed this model when I was in
Michigan State University, teaching prospective elementary school
teachers their first mathematics course. The course aimed at promoting
number sense at an elementary level. Given the limited ability of the
students to explain their mathematical ‘‘doings,’’ I found myself look-
ing for tools not only to help the students’ reason about a mathemati-
cal situation, but first and foremost to make them aware of the need
for this reasoning.
The core of the TLS in which the teaching–learning experience takes
place is perceived as consisting of three sub-spaces: the contextual, the
abstract, and the physical-abstract. These three sub-spaces differ in the
kinds of reasoning employed in each, in the language used in each and
in the kinds of activity performed in them. The transition among the
three sub-spaces is effected by a goal-driven means of re-phrasing in the
language used in the new sub-space. The TLS model provides a frame
for relating various concepts across different representations and across
different situations and facilitates a critical discourse. A comprehensive
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support system surrounds the core of the TLS to address motivational
issues (see Figure 1).
There are many paths through the different sub-spaces of the TLS,
and many ways of using the model to promote reasoning and under-
standing. The main continuum provides tools for studying one specific
mathematical situation: mathematical situation – contextual situation –
abstract set model – physical abstract situation – contextual situation
– mathematical situation. Other continuums follow chronological pro-
cesses: whole number to fractions or additive to multiplicative continu-
ums. The latter two continuums are interrelated and embedded in each
other and in each of the applications of the main continuum.3 Next, I
describe the different sub-spaces vis-a-vis a description of an actual
class engagement aimed at adding meaning to the mathematical algo-
rithm 3 14� 2 1
5 ¼ 134 � 11
5 ¼ 134 � 5
11 ¼ 6544 ¼ 1 21
44 and prove it (reason
about it). Some of the activities in the class were based on a whole
class forum and others were based on individual student work.
The Contextual Sub-Space
By the contextual sub-space I refer to the level of the story problem.
Thus, the language here is real and is related to the ‘‘story,’’ and so
are the activities, as well as the reasoning. The transition from the
Figure 1. The Teaching–Learning–Space model.
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contextual to the abstract space is motivated by the ‘‘problem,’’ which
is first stated in the ‘‘contextual language.’’
In Class
We4 begin by constructing a real problem for the mathematical prob-
lem: Since we are dealing with division, we think about whole number
division, for example 6� 2: We try to come up with a real situation of
sharing 6 between 2, or ‘‘measuring’’ how many 2s are in 6. We look
at real problems that also make sense in the case of fractions. (thus,
we have x pizzas to share among y people’ is inappropriate). Eventu-
ally we agree on something like: A gallon of ice cream is made with 2 15
cups of sugar. Liz has 3 14 cups of sugar. How much ice cream, in gal-
lons, can she make?5 This is followed by a discussion: Will she make
at least 1 gallon of ice cream? 2 gallons? More? Why? The reasoning
here is based on ‘‘she has more than 3 but fewer than 4 cups of sugar
– so she’ll make more than 1 gallon but fewer than 2 gallons of ice
cream.’’ This discussion takes place without any actual writing, draw-
ing or calculating. We conclude the discussion with a real strategy to
find out ‘‘how many gallons’’ (whole number language) of ice cream
she can make. For example, put the amount of sugar that is required
for each gallon of ice cream in a separate heap, until there is no more
sugar left, then count the ‘‘number of heaps’’ (whole number
language). Thus, we first build the ‘‘story’’ – the modeling in the next
phase will take us back to the division of fractions.
The Abstract Sub-Space and the Abstract-Set-Model
By modeling the contextual situation we move to the abstract sub-
space and use abstract sets-language. Complex situations involve
staging or breaking down procedures and using the model iteratively;
but the Basic Model refers only to the basic binary operations and
has three components, and a theoretical goal associated with it. The
model components are: The Number of Disjoint Sets that are in-
volved in the situation (first); the Number of Elements in each such
whole set (second); the Number of Elements in the Union Set (third).
The theoretical goal stems from the desire to ‘‘complete’’ the model
(i.e., to find the missing component), or to ‘‘describe’’ the relation-
ship between two of the model’s components. In the latter case, we
would refer to it as a relational-theoretical goal.
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Hence, we define two basic types of the Abstract Set Model
(Figure 2): The additive model and the multiplicative model. While a
constant number (2) of disjoint sets that are involved in the situation
characterizes the additive model, it is the equal size of the disjoint sets
that characterizes the multiplicative model. In both models, the third
component is the number of elements of the union set of all the
disjoint sets. The contextual space determines the theoretical goal for
the abstract space, which is therefore expressed in sets-language. If the
theoretical goal is to expose the third component (i.e., number of ele-
ments in the union set), then the model represents an addition (additive
model) or multiplication (multiplicative model) situation, whereas if the
theoretical goal is to expose the second (i.e., number of elements in
each whole set), then the model represents a subtraction (additive mod-
el) or a division (multiplicative model) situation. The latter is tradition-
ally referred to as the partitive approach to division. If the theoretical
goal is to expose the first component (number of sets), which is rele-
vant only in a multiplicative model, then the model describes what is
usually referred to as the measurement division approach. Relational-
theoretical goals in the additive model could describe either additive
relations (bigger–smaller) that are basically subtraction situations, or
multiplicative relations, which are ratio (or proportion) situations.
In Class
Since we do not have ‘‘exactly’’ two sets (heaps) and since all of our
sets (heaps) must have the same number of elements (same number of
cups of sugar), the modeling of the real strategy leads to a multiplica-
tive model; where the number of sets is unknown, there are 2 15 elements
in each whole set and 3 14 elements in the union set; thus the theoretical
Figure 2. The abstract set model.
388 DVORA PERETZ
goal is to ‘‘expose’’ the number of sets. The reasoning here will revolve
around the appropriateness of the other models, too. For example,
could it be that 2 15 is the number of sets and 3 1
4 is the number of
elements in each whole set? That would suggest that we have more
than 2 sets each with more than 3 elements, so in total we need to
have more than 6, which we do not. What would this imply in the real
situation?
The theoretical goal leads to a practical goal: To do ‘‘physically’’ in
order to achieve the theoretical goal (i.e., to join sets, to take-away
elements, to put-equally into sets, etc.).
In Class
We set the practical goal: to use all of our resources (3 14 elements) to
make as many sets as possible, each with 2 15 elements (whole number
language), which makes the transition to where we actually do the
mathematics.
The Physical-Abstract Sub-Space
The most significant feature of this space is the (mental) ‘‘physical’’
doings and language that are applied to the abstract objects (sets and
elements). These physical doings also serve to reason ‘‘physically’’
about the situation. All the doings here are accompanied by drawings
to show how, and by words to explain why.
In Class
The doings of a student are described in Figure 3. Here we see that
the student starts making sets of the required size. He first cuts up one
element into five equal pieces and then he puts 2 whole elements and
one fifth of an element together to make up one set. Since there are
not enough elements to make one more whole set, the student puts all
the leftovers together to make as ‘‘many’’ (whole number language)
sets as possible. Now, the student needs to count the number of sets
he made. To do this, he rephrases the ‘‘names’’ of the elements (uses
different units, as the original unit of 1 element is not practical any-
more), by cutting up each fourth into 5 equal pieces and each fifth
into 4 equal pieces to get many ‘‘new’’ elements ð 120Þ:
We also suggest and discuss alternative ways. For example, chang-
ing the unit of reference in the beginning by cutting each 14 of an
element into 5 equal pieces and each 1/5 into 4 equal pieces we move
389ENHANCING REASONING ATTITUDE
to work with 120 of an element instead of one whole element. Thus, we
might rephrase our problem as the whole number problem of: 65� 44:Finally, we take our ‘‘products’’ back to.
The Contextual Realm
To insert/relate our products/results into the real situation; 1 2144 what?
Does it make sense? Did we get a negative number for the number of
Figure 3. The physical doing of 3 14� 2 1
5 :
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gallons? Did we get more than 1 gallon and fewer than 2 gallons, as
we estimated in the beginning? We also discuss our results in terms of
the measurement approach. For example, we ‘‘measure’’ how much
sugar Liz has by the ‘‘number of gallons of ice cream it can make’’ (not
by cups) or by a ‘‘special measuring cup’’ equal to the size of 2 15 cups;
Then back to.
The Mathematical Realm
To discuss the mathematical principles that underline our ‘‘doings,’’
such as issues of commutative, associative, distributive, multiplica-
tive, and additive inverses. What are the ‘‘physical’’ sources or the
‘‘physical’’ indications for them in our physical doings? For exam-
ple, what does the ‘‘flipping’’ mean? Why does it yield the ‘‘true’’
answer to our mathematical challenge? Looking at both the mathe-
matical algorithm and at our physical-abstract doings (Figure 3),
we try to identify the roles of each number in both procedures.
Here ‘‘we’’ means teacher and students – I am describing–summa-
rizing what we did in class: usually it is the students who do most
of the talking. We see that 120 plays a role in the physical abstract
realm but not in the mathematical. How is this? A closer observa-
tion reveals that, in order to be able to describe the number of
elements in all the sets in the situation, we need a common unit
of reference to describe the fourths and the fifths of an element.
Thus, we cut each fourth into five equal pieces and each fifth into
four equal pieces to get our ‘‘new’’ elements 120. Using 1
20 of an ele-
ment as the new unit of reference to describe our sets re-phrases
our practical goal: to make sets of 44 120-elements when we have a
total of65 120-elements. We can link these facts to the original prac-
tical goal of making sets of 115 elements when we have a total of 13
5
elements to explains the ‘‘cross’’ multiplication of the numerator of
the first fraction by the denominator of the second (13� 5 = 65),
and of the numerator of the second fraction by the denominator
of the first (11� 4 = 44). Now since our theoretical goal was to
discover how many sets we have, not only do we see that the
‘‘new’’ units of reference ( 120-elements in this case) are not relevant
in the final product, but we also see that the question of how
much of the second set we made calls for a fraction notation
where the 44 is the denominator and the 65 is the numerator.
This results in the ‘‘flipping’’ effect.
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THE MAIN PRINCIPLES OF THE TLS APPROACH
The TLS approach reverts to natural–physical doings in trying to pro-
mote a natural or intuitive understanding of the basic mathematical
concepts as a well-established, firm basis for the understanding of the
more abstract, formal concepts. The physical doings serve to reason in
a ‘‘practical’’ manner about the situation on hand. For example:
‘‘3� 12 ¼ 6’’ since I have physically made 6 sets, each having 1
2 ele-
ments until my resource set of 3 elements is exhausted. Alternatively, I
put all my 3 elements equally into ‘‘all’’ my 12 empty sets. Since each
whole set in the situation is made up of two such ‘‘12 sets’’ and since
‘‘equally’’ means that there are the same number of elements in both
halves of a set, i.e., 3, then there are 6 elements in one whole set. In
both cases we support our arguments by presenting ‘‘physical’’ evi-
dence by drawing all the stages of our ‘‘doings.’’
Instead of concentrating on re-teaching the basic mathematical
arithmetic concepts, it employs a mathematical-like critical discourse
about these mathematical concepts using non-mathematical language.
The mathematical-like discourse is a ‘‘formalization’’ of informal
methods: it uses pre-defined structures to lead the otherwise ‘‘infor-
mal’’ class discussions, as was illustrated in the third section. This dis-
course emphasizes the asking of the right ‘‘whys’’ and leads the
students through finding appropriate lines of reasoning to answer
these ‘‘whys.’’ From my experience, this critical approach also helps
raise the students’ attention level, which is rather low when they study
topics that they regard as already known.
The ‘‘doings’’ in class, the mathematical-like discourse, and the
rigid use of our model, are tied explicitly to the kinds of doing and the
rigid argumentation discourse used in mathematics. For example, before
‘‘doing physically’’ to ‘‘prove’’ the distributive law with our model and
our language, we discuss the way a mathematician would go about
proving it, tying mathematical definitions and operations to our basic
‘‘doings’’ (break-down, join, stage etc.) and mathematical arguments
to our ‘‘physical’’ proofs.
Building on a deep understanding of simple whole number situations as a
basis for all further learning we discuss mathematical situations such
as 12 16� 1 3
4 using whole number language: ‘‘we have 1 34 groups ...’’ rather
than ‘‘we have one group and three quarters of a group.’’ The use of whole
number language motivates the use of whole number (‘‘natural’’) models to
deal with ‘‘new’’ non-natural kinds of numbers: a division like this: 12 16� 1 3
4 ;
is much the same as a division like this: 6� 5, so, we need to do the same!
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Using the abstract model, which conceptualizes all basic mathemati-
cal situations as the same, to channel and to mold reasoning – ‘‘filling
in’’ the abstract set model and setting the theoretical and practical
goal accordingly: 1 34 sets each having an unknown number of elements
and the union-set has 12 16 elements; A Multiplicative Model; Theoreti-
cal Goal: To reveal the number of elements in each set; The practical
goal is to put equally all the 12 16 elements in all the ‘‘empty’’ 1 3
4 sets,
until we exhaust our resource set. Figure 4 presents a student’s ‘‘physi-
cal’’ doings.
There are various ways in which the TLS approach promotes a
reasoning attitude: Any statement is accompanied by answers to: Why
is it true/false? Why is it important/not important? Each situation is
explored thoroughly rather than employing a ‘‘task-oriented’’ explora-
tion. The students carry out massive (i.e., lots of) reasoning tasks such
as the above and others, and massive investigations (trying to reason)
of other students’ understandings and solutions.
The TLS approach also contributes to developing awareness of the
meta-cognitive processes. This is done by using the abstract set model
to compare the same/different situations, reasoning, and doings; by
using the same language/doings in comparable situations; by reasoning
about the thinking: ‘‘Why this procedure and not another,’’ etc. and
by employing a holistic approach working up from the mathematical
situation through the contextual to the abstract and then back to the
‘‘physical-abstract’’ realm and again for a closure to the contextual
and to the mathematical strata.
SCAFFOLDING AND CHANNELING REASONING
There are many applications of the TLS that make mathematics
more meaningful and more accessible to the students. One of its
most significant applications is the scaffolding of the understanding
of others. To illustrate, I describe how students make sense of an
unusual partial solution for a long division problem (Figure 5). The
students were asked to justify, to reason and to ‘‘finish’’ Jack’s
work. Only those who wrote down both options for the multiplica-
tive model (see Figure 6) and searched for ‘‘clues’’ in Jack’s work
to try and understand which model underlines his doings,
succeeded.
Each model ‘‘leads’’ to a different practical goal and setting (see
Figure 7): Model A leads to ‘‘put equally all 3674 elements into 87
393ENHANCING REASONING ATTITUDE
empty sets’’ and Model B leads to ‘‘make as many sets as possible, 87
elements each, with all your 3674 elements.’’
If Jack was thinking about Model A, we need ‘‘to see’’ 87 sets (or
something close to that) filling up. Since nowhere in Jack’s work do
Figure 4. Physical doings of 12 16� 1 3
4 :
394 DVORA PERETZ
we see 87 ‘‘empty sets’’ or anything close, nor do we see anything that
might be understood as ‘‘putting equally,’’ we cannot really convince
ourselves that he has opted for Model A. That leaves us with Model
Figure 5. Jack’s partial doings of3674� 87:
Figure 6. The two models.
Figure 7. Physical settings of models A and B.
395ENHANCING REASONING ATTITUDE
B. Here he is supposed to start only with his resource set, and we
need to see some sort of ‘‘making of sets,’’ each with 87 elements.
Using these glasses to look at Jack’s work, we see that he says ‘‘30
100s’’ which are 30 sets of a ‘‘fixed’’ number of elements. We can
now relate this to the practical goal in Model B ‘‘make sets of size
x.’’ With this in mind, we can follow his work when he makes sets
of hundreds and then ‘‘corrects’’ them to the desired size. This also
explains the 13s that we see in his work, about whose derivation few
students at the outset had any clue. Now we can finish his work in
the same way, see Figure 8.
DISCUSSION
There are several aspects of the TLS approach that are relevant to our
discussion about reasoning: asking the ‘‘whys,’’ reasoning ‘‘physically’’
Figure 8. The physical reasoning of model B.
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about mathematics, using the abstract set model to channel the
reasoning and the holistic path that connects the formal to the infor-
mal and to the semi-formal. But perhaps the most important question
is whether this approach actually changes a student’s attitudes towards
reasoning. One could not expect a drastic change in attitudes after a
period of one semester. Yet this approach makes the asking of the
right ‘‘why’’ and supporting one’s answer with a relevant ‘‘proof’’ an
integral part of the discourse. Asking ‘‘why’’ creates the need for proof
(Dreyfus & Hadas, 1996). The students were constantly engaged in
explaining each step of their contextual, abstract, and physical
‘‘doings,’’ and their motivation for doing so at different levels and in
the different ‘‘languages.’’
Asking ‘‘why’’ promotes the urge to reason. The students were
exposed to the ‘‘right’’ ‘‘whys’’ to ask and they were confronted by
‘‘whys’’ to which they had no immediate answer. By the end of the
semester, not only were most of the students able to ask ‘‘good’’ ques-
tions and offer ways to find answers to these questions, but they also
understood the need to ask these questions. This could be seen in the
students’ weekly reasoning assignments, as well as in the class discus-
sions, as illustrated in the examples presented in the article. This
agrees with Richards (1991, p. 68) portrayal of a constructivist teach-
ing approach: ‘‘The teacher must design tasks and projects that
stimulate students to ask questions, pose problems, and set goals.’’
The TLS approach, similar to that of Moore and Schwartz (1994),
facilitates conceptual conjecture and justification and creates a culture
in which reasoning and demonstration became a social phenomenon.
Doing mathematics ‘‘physically’’ offers informal ‘‘proofs’’ and justifica-
tions; it serves in place of formal theorems and logic, which are used
by mathematicians to prove/understand mathematical theorems. By
‘‘physically’’ tracing each step of the ‘‘statement’’ (solution algorithm,
commutative rule, etc.), we prove it to be true or false. Moreover, the
‘‘physical-abstract-doing’’ serves what mathematicians refer to as
insightful proof, a proof that offers a ‘‘deep’’ understanding of the
situation at hand.
The abstract set model provides a channeling device to scaffold the
reasoning process. It helps the students to analyze the abstract mathe-
matical situation and leads them to construct a practical strategy to
solve it. Many students have difficulties deciding ‘‘what is next’’ in
order to construct a valid line of reasoning; the abstract set model and
the associated theoretical goals with their ‘‘fill in’’ structure lead the
students from one stage to another and help them decide ‘‘what is
397ENHANCING REASONING ATTITUDE
next’’ (see Richards’, 1991, quote in the conceptual framework
section).
The use of the Abstract Set model together with the ‘‘doings’’ in
the physical-abstract realm accentuates the differences between addi-
tive and multiplicative structures. It channels the students’ reasoning
in distinguishing between these structures – an area that is long known
to be one of great difficulty for students. Making the different charac-
teristics of the two models (the additive and the multiplicative) explicit
in the many different situations that we explore in class helps the stu-
dents to see the similarities and the differences between additive and
multiplicative situations; this, in turn, helps them to make the distinc-
tion when necessary. The students were constantly required to relate
various representations (i.e., contextual, formal-mathematical,
abstract-physical) and ‘‘doings’’ across situations and across concepts.
This holistic approach grants the students a higher degree of flexi-
bility in dealing with mathematical problems. Like many of the con-
structivist approaches to the teaching and learning of mathematics, the
TLS approach also emphasizes the importance of both aspects of the
mathematical experience: the concrete and the abstract, and the inter-
play between them. The physical-abstract realm offers a mediator con-
text in which students might understand the links between the concrete
situation and the abstract mathematical situation.
The prospective elementary school teachers students were encour-
aged to construct their own individual ‘‘doings;’’ the more advanced
students were challenged to also try ‘‘awkward’’ procedures, and not
only the most ‘‘efficient’’ one. For example: ‘‘...try to put 12 elements
into each set first, even if it makes the ’leftovers’ in the resource set an
’ugly’ number....’’ The use of ‘‘ugly’’ numbers veils intuition and there-
fore forces students to turn to logical arguments. Here, students could
test their understanding of the mathematical situation as well as their
reasoning skills.
In the context of abstract mathematics, the ‘‘physical’’ ‘‘doings’’
help strengthen the students’ conviction (Fischbein and Kedem, 1982)
by calling on their intuition (Fischbein, 1987) for certitude. The differ-
ent ‘‘doings’’ and reasoning in the TLS offer proofs that explain
(Hersh, 1993), as well as validation and demonstration (Selden &
Selden, 1995). Many students appreciate the concise view of the situa-
tion that the model affords, as well as the rigid frame it provides to
steer their ‘‘doings’’ and reasoning in a new situation. Also, they seem
to enjoy the flexibility that using the non-formal mathematical
language permits. By the end of the semester it was evident that the
398 DVORA PERETZ
quality of the class discussions had changed for the better. By that
time students could discuss the whole mathematical situation – from
constructing a ‘‘good’’ problem-story, to the ‘‘doing’’ to solve it, and
could reason about all its different aspects. Judging from the flexibility
students exhibited by the end of the semester in their response to the
many reasoning tasks, one could expect that the students’ ability to re-
spond to their future students’ questions was likewise enhanced.
Some readers might feel, as did a few of my students, that this
approach makes things more complicated. However, one needs to
remember that the TLS approach is not designed for teaching the
arithmetic mathematical concepts. Rather, its main goal is to promote
within the students reasoning skills and reasoning attitudes in the con-
text of arithmetic; indeed this is a much harder task. When things are
simple, students treat them as trivial and find no need to justify them
or to reason about them. The critical approach puts the ‘‘already
known’’ concepts into a new, more complex context. When students
try to accommodate the mathematical situation into the three-faceted
model they are forced to examine it from different viewpoints. The
requirement to reason about each of these steps not only helps them
develop appropriate lines of reasoning, but also makes reasoning an
integral part of any mathematical doing. This I believe is a step to-
wards changing prospective elementary school teachers’ attitudes
towards reasoning in the context of mathematics; prospective teachers
might also take with them ideas about how to create a teaching envi-
ronment which promotes reasoning attitudes and skills within their
elementary school’s students.
NOTES
1 We would usually consider ‘‘flip the guy and multiply’’ as an image, a metaphor
or a remembered procedure, however, here as an answer to the question, Why, it as-
sumes the role of a ‘‘line of reasoning’’ or of an ‘‘individualized proof.’’2 This can be found in any basic linear algebra textbook, such as Linear algebra with
application by Steven J. Leon (1999), 5th edition. Upper Saddle River, NJ: Prentice
Hall.3 Usually, we begin by exploring addition situations which gradually evolve into
multiplication situations; when discussing addition we explore whole number con-
texts and move on to contexts which involve fractions (The basic assumption is that
students already know fractions). When getting into multiplication situations, we
again ‘‘meet’’ fractions, from yet another aspect, i.e., their ‘‘construction.’’ Here the
discussion ‘‘starts over:’’ we re-examine characteristics of the ‘‘new’’ constructs, ‘‘re-
define’’ operations on them and explore attributes of the ‘‘new’’ operations. In such
399ENHANCING REASONING ATTITUDE
ways our critical discourse is evolving in overlapping circles.4 We here relates to myself as teacher and the students in my class.5 I recognize that this problem is not very realistic, but it demonstrates in a real way
the need for division of fractions.
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Center for Advanced Studies in Mathematics
Ben Gurion University
P.O. Box 653
Beer Sheva, 84105
Israel
E-mail: [email protected]
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