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Setting the Context for Mathematics in Context
Vicky L. Kouba
with
Özlem Çeziktürk
Susan A. Sherwood
Chia-Huan Ho
University at Albany
State University of New York
"Using mathematics in applied situations leads to
a deeper understanding."
(NCTM, 1998, p. 93)
Teaching, learning, and assessing mathematics in context requires careful
thought and planning. This paper will address context in assessment: assessment
using tasks or situations that illustrate the applicability of mathematics
in other school subjects, in the world of work, or in the students' personal
lives.
The use of context in mathematics helps to:
- Improve students' ability to demonstrate their understanding of mathematics,
and
- Facilitate the development of greater understanding of mathematics
principles.
Context should be employed carefully, however. As we illustrate in the
following examples, context can also obscure the mathematics and divert
the intended direction of the development of mathematical understanding.
We begin with an analysis of students' responses to tasks designed to
test their understanding of mathematical principles. After illustrating
how the contexts in which the tasks are posed influence students' performance,
we then consider the implications of that analysis for teaching.
In the current standards-based reform movement, students' mathematical
understanding often is measured using tests the students' teachers did
not design. Tests of this sort that "fall from the sky" require
students to answer questions in unfamiliar contexts and without benefit
of the knowledge of the teacher's expectations. All of the student responses
reported here are based on tasks that underwent careful design and pilot-testing,
but that were not developed by the students' teachers. The tasks are posed
in contexts with which the students are not necessarily familiar. As these
tasks illustrate, a student's familiarity with the context can have profound
influence on the student's performance.
Interference and Context
The Mathematics National Assessment of Education Progress (NAEP) is an
example of an examination that "falls from the sky." Students'
responses to a task from the1996 NAEP Mathematics Assessment illustrate
the influence of context on students' interpretation and response to a
mathematics task.
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Doghouse Task
Julie wants to fence in an area in her yard for her dog. After
paying for the materials to build her doghouse, she can afford to
but only 36 feet of fencing. She is considering various different
shapes for the enclosed area. However, she wants all of her shapes
to have 4 sides that are whole number lengths and contain 4 right
angles. All 4 sides are to have fencing. What is the largest area
that Julie can enclose with 36 feet of fencing? Support your answer
by showing work that would convince Julie that your area is the
largest.
Response Student A
In order to achieve maximum area with 36 feet of fencing, the
best plan would be to make a square area. The area inside would
be 81 ft2 while in other plans, the area would decrease.
Response Student B

This way the dog has enough room to run and play. Plus Julie
has room for the dog house.
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This task was designed to test students' understanding of the principle
that of all possible rectangles, a square has the maximum area for a given
perimeter. Student A's answer demonstrates understanding of the principle.
The task developers intended that the maximization of area be the first
(and only) condition to be met. Student B's response, on the other hand,
demonstrates an understanding of the requirements of confined dogs. That
is, Student B apparently decided the primary consideration was that the
enclosure allow the dog enough room to run. Anyone who has boarded a dog
at a kennel knows that dog enclosures are constructed to maximize length.
Thus, Student B's answer is a reasonable one for the practical
context. But is it reasonable in the context of taking a mathematics
test? In most test-taking situations, as was the case with this particular
NAEP item, being alert to the test-maker's intention is essential to scoring
well. Although we often assume that a familiar context will make understanding
a mathematics principle more easily demonstrated, the dog-enclosure task
illustrates how a student's personal knowledge about the context obscures
the test-maker's intent.
Invisibility and Context
Another example illustrates how context can render the mathematics invisible.
This task and the student's response are data from a research study investigating
students' understanding of multiplication and division (Kouba, 1991).
A second grade boy, who had responded correctly to multiplication and
division tasks presented in context, was asked to perform the following
task:
You have 18 apples that you want to have 3 horses share fairly.
You want to use up all the apples. How many apples does each horse get?
The boy was quiet for a moment and then responded, "One."
The interviewer, a bit nonplused, repeated, "One? Are you sure?"
"Yes," replied the boy, "one, because if you give a horse
more than one apple at a time it could get sick."
The boy's previous responses were evidence that the boy understood multiplication
and division. However, the context in which this item was presented made
the mathematics invisible to him. The youngster, who lived on a horse
farm in rural New York, had a knowledge base about horses quite different
from that held by the item designer. No amount of coaxing on the interviewer's
part could get the boy to violate the "one apple to a horse"
principle.
Avoidance and Context
The influence of context on performance is observed in older students
as well and may be even more pronounced when the context is intentionally
an integral part of the task as the following example illustrates. Pre-service
mathematics teachers in a graduate methods course were asked to respond
to the following task:
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Solvent Task
Solvents are used in many industrial and domestic situations to
clean food containers, machines and tools. The use of solvents,
even harmless ones such as water, pose serious environmental problems.
The technological problem posed by the use of solvents is how can
the use of solvents be minimized? A solvent-use situation that you
have encountered in your daily life is cleaning a paint brush.
Use the information below about cleaning a paint brush to develop
a mathematical model of the process.
A paintbrush has just been used and the owner wishes to clean
it. After the brush has been scraped against the side of the paint
can, it still contains 4 fluid ounces of paint. The owner dips
it into a quart of clean solvent and stirs well until the diluted
paint solution is uniform. After draining, the brush still holds
4 fluid ounces, part of which is paint and part solvent, since
the diluted solution is uniform. The process is repeated with
a fresh quart of solvent. Explain how you went about developing
the model.
One pre-service mathematics teacher answered:
I am really not sure how to answer this question. I don't think
solvents should be used. With the situation given, I think the
brush is not really being cleaned but truly being covered by solvent
and eventually the solvent overcomes the paint and breaks it down,
the paintbrush is cleaned depending on the amount of solvent used.
I feel that water could be used instead of solvents. If you wash
the brush out with water long enough, it will get cleaned out
and it is safer for everyone. (Adapted from the Engineering Concepts
Curriculum Project, 1970.)
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This response by a pre-service mathematics teacher is typical and illustrates
two important features. First, it demonstrates that the typical mathematics
graduate student does not understand solvents and solutions well enough
to be confident with the interpretation of the situation. Second, it shows
how a typical graduate student chooses to discuss the environmental issues
rather than to develop a mathematical model for the rinsing process.
Many students ignore even the environmental issues, and question the task's
appropriateness as a measure of mathematical understanding. These students
are critical of the amount of reading, writing, and information about
solvents required for successful performance.
Why do students discuss the environmental issues or critique the task
rather than develop the mathematical model? One plausible explanation
is based on the fact that the majority of pre-service teachers find the
mathematical task of developing a model for rinsing difficult or impossible.
Thus, we propose that more sophisticated individuals may respond to a
task using context to avoid revealing that they do not have the mathematics
knowledge required to answer the question posed.
Assumptions and Context
Tasks posed in context often require individuals to make assumptions on
which to base their responses. These assumptions are often implied rather
than specifically stated. When the assumptions of the student are the
same as those of the task designer, the response matches the scoring standard
and the response gets the full score. However, as our next example illustrates,
if an individual bases a response on an alternative assumption, it may
be marked wrong.
A group of middle and high school mathematics teachers in a professional
development workshop were developing scoring standards for mathematics
tasks. They began the development process by writing individual responses
to the following task:
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Pizza Task
Your class has decided to have pizza for its end-of-the-year
party. You are trying to decide which pizza store has the cheapest
price. The local pizza stores and their prices are listed below.
Pizza Prices
| Sam's Pizza House |
$8.50 |
8 slices per pizza |
| Pizza Palace |
$10.25 |
10 slices per pizza |
| Pizza & Stuff |
$6.25 |
6 slices per pizza |
Assume that there are 30 students in your class and that each
person (including our teacher) will eat two slices. Also assume
that the slices in the pizzas from the different stores are the
same size. Where should you buy the pizza? Please show all your
work and write a brief description of how you decided on your answer.
SOLUTION
Sam's Pizza House offers pizza at $8.50 for 8 slices. That comes
to $1.06 per slice.
Pizza Palace offers pizza at $10.25 for 10 slices. That comes
to $1.02 per slice.
Pizza & Stuff offers pizza at $6.25 for 6 slices. That comes
to $1.04 per slice.
From this analysis it appears that Pizza Palace is the cheapest
source of pizza. However we must also consider the number of pizzas
that must be purchased for each person to have two slices.
The class and the students together will eat 62 slices of
pizza. That means they would have to buy:
- 8 pizzas from Sam's Pizza House for $68.00
- 7 pizzas from Pizza Palace for $71.75
- 11 pizzas from Pizza & Stuff for $68.75
Thus it appears that the cheapest source of pizza considering
the number of pizzas that must be purchased is Sam's Pizza House.
(Danielson, 1997, pp. 146-147.)
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Then the teachers worked in two groups to develop consensus solutions,
with the middle school teachers in one group and the high school teachers
in the other. The middle school teachers assumed that only whole pizzas
could be purchased, whereas the high school teachers assumed that the
pizza could be purchased by the slice. The different assumptions yielded
different answers. When the teachers shared answers, they acknowledged
that neither group had even considered the other's approach.
The teachers discussed the task designers' scoring guide, which is based
on just one of the possible assumptions. The teachers concluded that if
they, as adults, were not aware initially that alternative appropriate
interpretations of the task were possible, it is unfair to expect their
students to analyze tasks for alternative interpretations and weigh the
multiple possibilities. At least, it is unfair until students have had
an opportunity to develop skills in exploring multiple assumptions or
interpretations of tasks, and until they learn that presenting multiple
perspectives is a performance expectation.
Teaching about Context
Our examples illustrate several ways in which placing tasks in context
makes it more difficult for students to demonstrate their understanding
of mathematics. One might argue that we just need to design better tests,
ones with tasks that are absolutely clear. However, contexts are rich
and complex, and rightly so. Almost any item, no matter how carefully
designed or fully piloted, still is open to alternative interpretation
by a divergent, creative thinker. The challenge posed by setting mathematics
in context is multifaceted and consequently requires diverse teaching
approaches to provide students with the skills necessary to complete the
tasks. Two approaches are described below.
The first method addresses the instances where context obscures the task
developers' intent. As a part of teaching students to see mathematics
in practical situations, teachers need to provide students with the opportunity
to become context-wise. Context-wise students remind themselves
of the kind of test they are taking. "Remember," the student
must think, "this is a test of my understanding of mathematics, not
the design of dog enclosures or keeping horses healthy." This approach
can work for older students, but is not as helpful for younger students
who have difficulty with some abstract levels of thinking.
In the second method, students learn to develop analytical skills for
communicating solution strategies and making assumptions explicit. Communication
such as the kind that occurred in the mathematics teacher workshop described
above makes students and teachers deeply aware of the interplay of mathematics
and context. This kind of communication, this sharing of why and how tasks
are approached can be made part of the day-to-day mathematics class. Developing
the skills required to make assumptions explicit and to test the assumptions
helps meet the challenge of mathematics tasks with multiple defensible
interpretations of mathematics in context. In other words, students learn
to identify and state their assumptions, and students learn to give multiple
answers when they see multiple possibilities.
The cartoon that follows demonstrates the spirit, if not the letter,
of our thoughts about the importance of communication and explicit statement
of assumptions.
(FOXTROT ©1999 Bill Amend. Reprinted with permission of UNIVERSAL
PRESS SYNDICATE. All rights reserved.)
Bill Amend, the cartoonist, reminds us that the vast majority of the
applied mathematics that students encounter in mathematics classrooms
and tests is contrived. The tasks, projects, assessments, and activities
students encounter in academic mathematics rarely come directly from the
students or from problems they pose. Thus, we, as adults, design learning
and testing situations to capture either our vision of daily life or our
approximation of the students' vision of daily life. Because the contexts
are contrived and because they originate from the adults' situated cognition,
there are many opportunities for misconceptions or multiple interpretations
of a context. We are not talking about responses with incorrect mathematics,
rather we are concerned with response where the mathematics, per se, is
correct, but something else related to context has "gone a bit awry"
from what was intended.
When the miscommunication or multiple interpretation happens in the classroom,
the astute teacher can capitalize extemporaneously on the differences
to build a rich discourse about multiple perspectives, the value of being
able to communicate clearly and convincingly, and the need to listen with
an open mind. Assessment environments require a bit more foresight in
terms of expectations and, in high stakes testing, flexible scoring guides.
This latter point, the need for scoring guides to allow for divergent
thinking, is a critical one for test-designers. It also is critical for
teachers who must advocate for students when scoring guides unduly penalize
the creative thinker or the students who know a context from a perspective
different from the test designers' intent. The challenge is to draw the
line between responses that exhibit true divergent thinking from those
of students who deliberately use context to hide a lack of mathematical
understanding.
Conclusion
Many teachers avoid using context in instruction, both because they do
not feel comfortable with it, and because the students would have problems
interpreting it. The students, on the other hand, avoid tasks that are
put in context because they do not know how to make the context transparent
enough to see the intended mathematics behind it.
The use of context in testing mathematics can be a rich and vital source
of information and can more accurately reflect authentic uses of mathematics.
However, students should be given ample opportunity to learn how to think
about, analyze, and respond to such items, and scoring guides for the
items must take into account the possibility of reasonable alternative
interpretations.
We suggest that understanding the context of mathematics in context,
as demonstrated by the ability to state assumptions and consider multiple
perspectives, will give a boost of confidence to teachers using "out
of the sky" tasks as an aid in instruction and to students dealing
with high stakes tests.
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