S11: Well, it does kind of like even, odd, even, odd and
so on. That’s pretty convincing but if they had a little
bit more examples like even, like 2 and then odd, 3, it
would be more making sense of it than just doing
even, odd, even, odd, even, odd (D2A06, Interview,
February 27, 2009).
S12: Theirs is kind of confusing because it goes like
even, odd, even, odd and even, odd but it doesn’t show
you like if you take this one, it says 5 and 6, it would
equal like the odd number. It just shows you what the
answer would be but also telling you (D1B04, Inter-
view, February 23, 2009).
S6: I’d tell them to put examples in there that improve
the fact is right so that people can see that it’s true
(D2A09, Interview, February 27, 2009).
S13: Just personally, I’d just rather be looking at pic-
tures and numbers than words. Language arts isn’t my
favorite class so (D3A15, Interview, March 2, 2009).
The seventh-grade students we interviewed seemed to
view examples as a tangible resource for students to follow
and make sense of the G argument. These excerpts also
illustrate that students seem to be taking into consideration
the audience who will be reviewing the argument, with a
concern for the reviewer’s understanding. Their improve-
ments align with the rationales they provided for choosing
the EB argument as more convincing; students in this
sample revealed an awareness of the importance in con-
structing arguments within reach of the classroom com-
munity, and a consideration in evaluating arguments
should be that the reader wants to “see that it’s true.”
Each of the four students who chose the G argument as
most convincing stated that there was not enough expla-
nation and suggested adding facts to support the examples.
One student suggested, “[Since] any even plus any odd
number is an odd number, [they] might want to say that in
here somewhere, because that would make more sense to a
person who’s trying to understand.” Although students
choosing the G argument as more convincing indicated
that referencing terms, definitions, and facts would
improve the EB argument’s power to explain, no student
indicated that having examples in a mathematical argu-
ment was problematic or unnecessary.
Results from analyses of students’ responses to the
second and third interview questions show a high degree
of alignment between the ways they claim an argument
could be improved and the reasons they cite for why
174
an argument is more convincing than another. Their
responses suggest that they have acquired very little in the
way of formal “rules” about written mathematical argu-
ments, as evidenced by the lack of modal verbs in their
responses. No response stated that one argument is more
convincing than another because it consisted of certain
features that mathematical arguments are supposed to
have, suggesting that students are not applying any learned
scheme for evaluating arguments and are instead evaluat-
ing arguments based on what they have observed to be
normative of arguments in mathematics classrooms.
However, we do see evidence in their responses of accul-
turation to the practices of justifying one’s reasoning in
school mathematics that we discuss, among other impli-
cations, in the next section.
Discussion and Implications
While students’ preferences for empirical arguments in
this study support the findings of extant research, one
contribution of this study is to illustrate students’ tenden-
cies to value an argument’s power to communicate over
other possible functions of proof. For all but four students
who chose the EB argument as more convincing than the
G argument, they discussed the importance of examples
for making a clear and comprehensible argument. Stu-
dents’ responses reveal that they are valuing an argument’s
power to communicate over other functions when engag-
ing in justification in school mathematics.
Students’ responses to how they would improve an argu-
ment to make it more convincing highlight the interdepen-
dence between how students ascertain the truth of a
statement and how they persuade others of the truth of a
statement. Statements like “Because if you’re like a visual
person, like me, you have to see it on paper” reflect stu-
dents’ tendencies to assume that a convincing argument
(one that persuades another person) is an argument that
clearly demonstrates and communicates with illustrations,
examples, drawings, and words. More importantly, though,
such responses reveal the function that proving serves in
middle-grade mathematics. The statement “if you’re a
visual person” indicates that the student is aware of how the
argument will be communicating knowledge to another
person, and an argument can only be convincing if the other
person can comprehend it. Attention to an argument’s
facility in communicating mathematical knowledge was a
strong theme throughout the interview responses.
The findings of this study also distinguish reasons why
students tend to prefer examples in mathematical argu-
ments. While several of the responses noted how
examples were useful in demonstrating or “showing” the