ISSN 2087-8885
E-ISSN 2407-0610
Journal on Mathematics Education
Volume 12, No. 2, May 2021, pp. 223-238
223
INDONESIAN MATHEMATICS TEACHERS’ KNOWLEDGE OF
CONTENT AND STUDENTS OF AREA AND PERIMETER OF
RECTANGLE
Wahid Yunianto
1
, Rully Charitas Indra Prahmana
2
, Cosette Crisan
3
1
SEAMEO QITEP in Mathematics, Jl. Kaliurang, Condongcatur, Depok, Sleman, Yogyakarta 55281, Indonesia
2
Universitas Ahmad Dahlan, Jl. Pramuka 42, Pandeyan, Umbulharjo, Yogyakarta, Indonesia
3
University College London, Gower St, Bloomsbury, London WC1E 6BT, United Kingdom
Abstract
Measuring teachers' skills and competencies is necessary to ensure teacher quality and contribute to education
quality. Research has shown teachers competencies and skills influence studentsperformances. Previous studies
explored teachers’ knowledge through testing. Teachers' knowledge of the topic of area-perimeter and teaching
strategies has been assessed through testing. In general, items or tasks to assess mathematics teacher knowledge
in the previous studies were dominated by subject matter knowledge problems. Thus, it seems that the assessment
has not fully covered the full range of teacher knowledge and competencies. In this study, the researchers
investigated mathematics teachers’ Knowledge of Content and Students (KCS) through lesson plans developed
by the teachers. To accommodate the gap in the previous studies, this study focuses on KCS on the topic of area-
perimeter through their designed lesson plans. Twenty-nine mathematics teachers attended a professional
development activity voluntarily participated in this study. Two teachers were selected to be the focus of this
case study. Content analysis of the lesson plan and semi-structured interviews were conducted, and then data
were analyzed. It revealed that the participating teachers were challenged when making predictions of students'
possible responses. They seemed unaware of the ordinary students' strategies used to solve maximizing area from
a given perimeter. With limited knowledge of students' possible strategies and mistakes, these teachers were
poorly prepared to support student learning.
Keywords: Knowledge of Content and Students, Mathematics Teacher, Area and Perimeter, Teachers’ Skills
and Competencies
Abstrak
Mengukur keterampilan dan kompetensi guru diperlukan untuk memastikan kualitas guru dan berkontribusi pada
kualitas pendidikan. Penelitian ini menunjukkan bahwa komptensi dan keterampilan guru mempengaruhi
performa siswa. Penelitian sebelumnya telah mengkaji pengetahuan gru melalui tes. Pengetahuan guru pada topik
keliling-luas dan strategi pembelajaran juga telah dikaji melalui tes. Pada umumnya, banyaknya soal pada tes
didominasi oleh soal-soal tentang pengetahuan subjek yang diajarkan. Oleh karena itu, asesmen seperti ini belum
mencakup kesuluruhan pengetahuan dan kompetensi guru. Pada studi ini, peneliti menginvestigasi pengetahuan
guru matematika tentang KCS pada rencana pelaksanaan pembelajaran yang mereka kembangkan. Untuk
mengakomodasi kesenjangan pada penelitian sebelumnya, penelitian kali ini berfokus pada pengetahuan tentang
konten dan siswa (KCS) pada topik keliling-luas pada rencana pelaksanaan pembelajaran. Dua puluh Sembilan
guru matematika yang sedang mengikuti pelatihan peningkatan kompetensi secara suka rela mengikuti penelitian
ini. Dua guru matematika menjadi fokus penelitian studi kasus ini. Konten analisis dan interview semi terstruktur
dilakukan dan datanya dianalisis. Terungkap bahwa peserta ini mengalami tantangan dalam memprediksi
kemungkinan respon yang diberikan siswa. Mereka belum menyadari strategi siswa yang biasanya digunakan
untuk menyelesaikan persoalan memaksimalkan luas dari keliling yang ditentukan. Dengan pengetahuan yang
terbatas pada kemungkinan strategi siswa dan kesalahan siswa, guru ini kurang siap dalam mendukung siswanya
Kata kunci: Pengetahuan tentang Materi dan Siswa, Guru Matematika, Luas dan Keliling, Keterampilan dan
Kompetensi Guru
How to Cite: Yunianto, W., Prahmana, R.C.I., & Crisan, C. (2021). Indonesian Mathematics Teachers’
Knowledge of Content and Students of Area and Perimeter of Rectangle. Journal on Mathematics Education,
12(2), 223-238. http://doi.org/10.22342/jme.12.2.13537.223-238
224 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
Shulman (1986) refers to Pedagogical Content Knowledge (PCK) as the ways of representing and
formulating the subject that is understandable to others. Research have shown that student achievements
are more affected by PCK than Subject Matter Knowledge (SMK) as the quality of instruction is related
to PCK (Baumert et al., 2010; Hill, Rowan, & Ball, 2005; Hill, Ball, & Schilling, 2008). As the use of
SMK terminology varies, SMK in this paper refers to common content knowledge (CCK) which is part
of SMK (see Figure 1).
Hill, Ball and Shilling (2008), in seeking to conceptualize the domain of effective teachers'
unique knowledge of students' mathematical ideas and thinking, proposed the following
domain map for mathematical knowledge for teaching (see Figure 1) (White, et al., 2012,
p.394).
One specific aspect of PCK is the Knowledge of Content and Students (KCS). KCS is ‘knowledge
that combines knowing about students and knowing about mathematics (Ball, Thames, & Phelps, 2008,
p. 401). It consists of anticipating what students are likely to think about, what they could find confusing
or complicated, and what students are expected to do mathematically to complete the chosen task.
Figure 1. Domain map for mathematical knowledge for teaching (Hill, Ball, & Schilling, 2008, p. 377)
There are some teacher assessment models which measure knowledge for teaching. The Teacher
Education and Development Study in Mathematics (TEDS-M) is one of the international assessments
intended for pre-service mathematics teachers (Tatto et al., 2012). Some researchers assert that the
Assessment of Teachers’ PCK could be done through micro-teaching (Setyaningrum, Mahmudi, &
Murdanu, 2018; Ünver, Özgür, & Güzel, 2020). In the case of pre-service teachers, they have challenges
with student’s thinking, mistakes and responding (Korkmaz & Şahin, 2019; Setyaningrum et al., 2018;
Ünver et al., 2020). It makes sense as they have limited teaching experiences or even have not taught
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 225
yet. For in-service teachers, Baumert and Kunter (2013) developed instruments to measure teacher’s
professional competence (COACTIV). The COACTIV adopted the three main core knowledge CK,
PCK and PK from Shulman’s work and extended it.
As one of the ways, testing is used to assess teachers. The Ministry of Education and Culture
(MoEC) of the Republic of Indonesia has also implemented Teacher Competency Tests (TCT) to
evaluate teachers’ knowledge. The result of this assessment is both to evaluate teachers and to provide
support for them (Widodo & Tamimudin, 2014). However, the content of this assessment is commonly
dominated by SMK, in this case within the mathematical problems. It seems that the PCK has not been
measured fully through this wide assessment. Another study using testing faced challenges in measuring
teachers’ knowledge (Fauskanger, 2015). An interesting finding of a study of pre-service teachers is
that they possessed higher PCK scores than SMK from limited test items (Kristanto, Panuluh, &
Atmajati, 2020). A case study in South Korea revealed that teachers with sufficient SMK of a certain
competence/ topic faced challenges in incorporating KCS and KCT of that topic (Lee, Capraro, &
Capraro, 2018). Therefore, testing to measure teachers’ knowledge still face challenges.
Lesson plans are considered to play an important role in teaching and learning. Having a good
lesson plan is important in ensuring that learning would take place during the lesson (Jones & Edwards,
2010). Academics argue that the key determinant of success in teaching is the effectiveness of planning
and how well a plan is carried out in the classroom. Effective lesson planning considers possible
classroom problems and how to tackle them adequately (Jones & Edwards, 2010). In the common
Japanese lesson plan, it contains detailed instruction so that teachers can easily understand it when
reading it (Nakahara & Koyama, 2000). Japanese lesson plans also include possible student solutions
and errors. The blackboard is also carefully planned. Called, ‘Bansho’, which anticipates and tries to
elicit student mathematical thinking and student thinking schema for solving the given problems.
In developing lesson plans, teachers integrate their knowledge, such as subject matter knowledge
and pedagogical content knowledge (An, Kulm, & Wu, 2004; Burns & Lash, 1988; Simon, 1995). A
study in Australia revealed that the teacher, in planning a lesson, gave attention to students’ engagement
(Clarke, Clarke, Roche, & Chan, 2015). The students’ engagement involves a choice from many
pedagogical strategies, all designed to motivate the students to engage with the topic. It has been shown
by several studies that novice teachers improved their PCK by teaching and preparing to teach
(Turnuklu & Yesildere, 2007). There is a reciprocal relationship between teacher thought process
(including planning) and teachers actions, the latter much influenced by the former (Clark & Peterson,
1986; Superfine, 2008). In other words, teacher classroom practices are influenced by a complex mix
of teacher beliefs, attitudes knowledge and intentions Therefore, arguably it is possible to look at teacher
lesson plans to investigate their knowledge. The illustration of a model of teacher knowledge and
planning can be seen in Figure 2.
226 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
Figure 2. Model of teacher knowledge and planning (Burns & Lash, 1988, p. 382)
Carle (1993) has investigated several student misconceptions related to the area-perimeter topic.
A meta-analysis of research has shown some student misconceptions on area measurement was due to
area being taught together with perimeter causing many students to confuse area and perimeter (Watson,
Jones, & Pratt, 2013; Cavanagh, 2007). Cavanagh (2007) studied Australian Year 7 secondary students
and reported students experienced difficulties dealing with area concepts because of the above
confusion with perimeter. As a consequence, students used slant and perpendicular height
interchangeably. Zacahros & Chassapis, (2012) reported Greek Year 6 elementary students added the
base plus the height instead of multiplying base with height to find the area of a rectangle. Özerem
(2012) reported that seventh year secondary school students in Cyprus had a number of misconceptions
due to a lack of knowledge related to geometry, resulting in them using the wrong formula. This lack
of understanding of the concept of area resulted in students memorizing the formulas. Students who
learn through manipulating area seem likely to avoid misconceptions on area measurement (Watson et
al., 2013). It seems to make sense as they could manipulate and observe what changes happen by
reshaping a figure (Yunianto, 2015).
It has been shown that SMK and PCK of mathematics teachers influenced student performance
(Baumert et al., 2010). Thus, we should not expect teachers to deliver mathematics well if they do not
have mastered it and do not understand how to teach it. Kow and Yeo (2008) explored the importance
of SMK and PCK in the topic of area-perimeter from the planning of the lesson to its delivery. It was
found that teachers with strong SMK and PCK provided more freedom to students to approach the task.
Baturo and Nason (1996) evaluated first-year teacher education student understanding of subject matter
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 227
knowledge in the domain of area measurement and uncovered many misconceptions. Success was
related to their experience of learning the topic. John (2006) argued that novice teachers have difficulty
making predictions about student responses and how to respond to unpredicted situations they
encountered. In line with this, lack of mathematics pedagogical content knowledge of the teacher
potentially lead to students having misconceptions (Kow & Yeo, 2008).
This study intends to focus on a part of PCK, the KCS within lesson plans on the topic of area-
perimeter of a rectangle. It is necessary to obtain a fuller insight into teacher knowledge as it influence
students’ performance. Beside testing, there might be alternative way such as lesson plans to investigate
teachers’ knowledge. How are mathematics teachers prepare their lesson plans and how is PCK
integrated in their lesson plans? How are the KCS integrated in the lesson plans? In the next section,
the ways of gaining this insight will be discussed and the strategies used in collecting and analyzing the
data. Furthermore, the results and discussion sections will describe the KCS evident in the lesson plans
and the interviews with the respondents.
METHOD
This research involved humans and has been approved by IOE research ethics of University
College London (IOE.researchethics@ucl.ac.uk) as this is a part of completion of the first author’s
dissertation. This study administrated a case study approach. This approach suits this study as it does
not seek to generalize the findings but to gain deeper insight into the issue (Denscombe, 2010; Yin,
2014). The research subjects were the mathematics teachers in Yogyakarta and its surrounding
registered themselves to participate on PD organized by SEAMEO QITEP in Mathematics. Some
teachers teach across multi-grades. The first researcher who was facilitating one of the sessions asked
the participants to develop a lesson plan as part of the whole PD. It was done somewhere in the middle
of all complete sessions. As it is a case study, the researchers examined two selected lesson plans of
two mathematics teachers. The remaining lesson plans have not been analyzed due to time limitation.
The sample was chosen from twenty-nine teachers who attended a professional development (PD)
session, and two teachers were selected for the lesson plan analysis and interview. Additionally. these
teachers were selected based on their teaching experience; at least five years. The interview scenario
was a semi-structured interview, and the two teachers were interviewed together. The two teachers who
had been interviewed were a female teacher and a male teacher. They have different years of teaching
experience. The female teacher teaches in a city while the male teacher teachers in a rural area.
Participation in this study was voluntarily. The Indonesian mathematics teachers attending this PD were
teaching grade 7 to grade 9. The topic that would be taught was area and perimeter for grade 7. The
“Gold Rush/Mining” task was selected. This task was chosen because it is a problem-solving task and
has several ways to be solved on area-perimeter of a rectangle (see Figure 3). Additionally, the complete
Gold Rush activity showed the mistakes that students might do. Thus, it is considered as a good activity
to be explored to understand how teachers prepare this activity.
228 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
Figure 3. The Gold Rush problem (https://www.map.mathshell.org/download.php?fileid=1637)
To analyze the lesson plans, the researchers used content analysis. This method has the potential
to disclose many hidden aspects of what is being communicated through the written text’ (Denscombe,
2010, p. 282). From the lesson plan, the researcher would investigate to what extent the teachers’
knowledge of students’ conceptions and misconceptions is reflected in their written lesson plans (Table
1). The two lesson plans were coded to find themes by classifying instructions and KCS integrated in
the lesson plans.
Table 1. Knowledge of Content and Student (KCS) (Ball et al., 2008, p. 401)
No.
Knowledge of Content and Student
1.
The ability to anticipate what students are likely to think and what they will find confusing
2.
The ability to predict what students will find interesting and motivating when choosing a task
3.
The ability to anticipate how students are likely to solve a given task and whether they will find
it easy or difficult
4.
The ability to hear and interpret students’ emerging and incomplete thinking
By using Table 2, it is easy to differentiate instructions’ categories. These themes were useful in
providing information on what the lesson plans contained. It focused on whether or not, the teachers
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 229
included information about what students would do to the task (KCS). The data were presented
descriptively.
The two lesson plans were coded and analyzed. There were three types of instructions to refer to
with the codes. First, general instruction (GI) is where the teacher gives students instructions in a general
way. This type of instruction is relatively simple, short and contains the doer(s) and their actions (verb)
but leads to some mysteriousness (unclear). The second type of instruction is specific instruction with
no detail (SIND). This refers to specific action, which has more information than GI but lacks detail in
necessary aspects. The last type of instruction is specific instruction with detail information (SID). This
instruction provides more detail and clearer information. Some forms of SID are short and require no
detail, as it can be found easily or understood easily in other parts of the text. Looking through the
instruction types, the researcher seeks evidence of KCS on the lesson plans (Table 2).
Table 2. Coding for instructions
Code
Example 1
Example 2
GI
Teacher asks a question to students
Teacher asks students to present their work
SIND
Teacher asks a question to students about their
strategy.
Teacher asks two groups to present their
work
SID
Teacher asks a question to students about their
strategy. “what did you do and How did you
do it? How are you convinced with your
strategies?
Teacher asks two groups with different
strategies to present their work starting with
the group with less sophisticated strategy.
The two teachers were also interviewed to gain more insight. They were interviewed together
(focus-group interview). The researcher wanted to clarify what was written on the lesson plans and why.
Through a semi-formal interview style, data were collected through voice recording as well as video
recording. From the records, data were transcribed and analyzed.
RESULTS AND DISCUSSION
Using the codes, the lesson plans revealed some interesting findings. Teachers 1 (T1) and
Teachers (T2) have different proportions of the use of the instructions (Table 3). The percentage is from
type of instruction per total instructions written on the lesson plans.
Indonesian teachers follow the prescribed template of a lesson plan by MoEC. The template consists
of three main parts namely; introduction, main and closure. It also consists learning goals and how teachers
and students would do in the classroom.
230 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
Table 3. Proportions of the instructions
Instruction
T1
T2
GI
8 (35%)
6 (31.6%)
SIND
6 (26%)
7 (36.8%)
SID
9 (39%)
6 (31.6%)
Total
23 (100%)
19 (100%)
Based on the partition T1 used more instruction in the introduction and has less instruction in the main
body. Interestingly, T2 has more instructions in the Main body with detailed information. Compared to T1,
T2 had fewer total instructions, and detailed instructions (SID). From T2’s SID, there were several
instructions that provided information relating to PCK (Table 4).
Table 4. Comparison of Instructions
Code
Introduction
Main
Closure
T1
T2
T1
T2
T1
T2
GI
2
0
3
4
3
2
SIND
3
1
3
3
0
3
SID
7
2
1
4
1
0
Total
12
3
7
11
4
5
T1 put more details of what students would ask to her on her lesson plan. For instance: ‘Can I solve
it freely?’ has been put on her lesson plan. This is a proof of PCK in the lesson plan, but not specific to KCS.
Figure 4. Teacher 1 Lesson Plan
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 231
In addition, the way she would organize the discussion are provided in detail. This would provide
information to other readers/ teachers how the classroom discourse was managed (Figure 4). On the phase
of guiding the individual and group investigation which be rich of KCS. In this lesson plan, detail ways of
students might solve it or make mistakes and how to facilitate it have not been depicted.
The T2 lesson plan of rectangle using Gold Rush task depicted detailed information about a
possible student strategy (KCS). Figure 5 shows that T2 considered one strategy that students would
utilize by asking students to make a table. T2 prompted students to make a table and gave an example
to start with simple numbers. Within that table students would investigate the largest area by filling the
lengths and widths that added to 100. More interestingly, two examples with easy numbers were
provided to support students. Therefore, T2’s instruction can be understood as providing a method to
solve the task, with much support given to students.
Figure 5. Teacher 2 Lesson Plan of Gold Rush
After finding the largest area of the rectangle, students had to find the largest area by joining two
miners’ ropes and how would they join it. T2 also offered questions for students, revealing the
organization on their lesson plan. T2 has also provided students actions in Figure 6.
Figure 6. T2's lesson plan on organizing the classroom discussion
Students were expected to evaluate and generalize during discussion. Although it was unclear
what kind of evaluations and generalizations would be made. It would be clear if he put, for instance,
that the generalization would be that ‘the largest area would always be a square’. This generalization
might come out from students. In addition, it was not clear how T2 would organize the presentation, or
232 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
which group would present first. If there were two groups with different strategies or different
conclusions, it is not clear how it would be organized.
Teachers T1 and T2 have more than five-years teaching experience each. Based on the
questionnaire and interview, their schools are different in terms of location and studentsbackground.
These teachers themselves employed different abilities in solving the Gold Mining problem (Figure 3).
From the conversation below, it seems that they have three correct strategies or less to solve it: T1-Ms.
Excel integration and T2 -table, quadratic function and graph. However, there is a significant difference
between the two teachers. T1 allowed the students to solve the task freely (students’ own ways).
The interview with Teacher 1 showed that she has the ability to solve the problem.
R
:
Are there other ways T1?
T1
:
Yesterday, I just did that one.
T1
:
…just let students find the ways to solve it …. Then, I will let them know that there are some
ways to solve it. I give that opportunity to students
This teacher (T1) would allow her students to approach the task in their own ways. However, T2 had a
different way of letting students approach the task, providing only one strategy.
T2
:
To me, I could do it directly because I already knew it but to students if I want to students to
learn it, I make a table for them. If the table is not made, students will find it difficult to
solve it for students in my school.
R
:
So, you (T2), induce them by using the table?
T2
:
Yes, by the table.
R
:
What do you think, how many ways to solve it?
T2
:
To me, I did one way I know it directly it would be a square. I knew it already. But for
students, with table, students will measure the perimeter, area, so if the length is 5, how
long is the width, if the length is 10, how long is the width, and.., they will list it, this is how
I let them learn. If I do not do it they will have no clue to solve it.
From the transcript of T2, he seemed to only allow his students to use one strategy. He believed
that his students would not be able to approach the task without inducing the table. He has had previous
experiences where students were unable to complete a similar task.
T2
:
I have tried several times an easier task, for instance, given the perimeter of a rectangle and
how big is the area, changing from the perimeter to area, I let them do it and facilitated
them, but students were not able. For the story problem, the reading comprehension, the task
asks to go to the East, most of my students go to the West (metaphor).
T2
:
However, I have thought only one strategy, which is global to solve a task. … I, I... know at
least I understand my students' characteristic so that it will be difficult for my students. … It
is not possible to come up if I let them to do it freely. … I am so careful to give it the various
strategies because students would get confuse
To know how to solve the mathematical task, these teachers tried the problem themselves. During the
interview, T2 seemed to be familiar with the task and had three ways of finding the answer. Meanwhile,
T1 only thought of one strategy.
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 233
T2
:
By using the strategy of making rectangles with certain sizes and order them and estimate
the biggest area.
T2
:
To me, I did one way I know it directly it would be a square. I knew it already
T2
:
…instead of table, we can make the variable x, then I will be a quadratic function,
R
:
Are there other ways to solve it?
T2
:
For the time being, not yet, making rectangles and to the square
R
:
Do you think there are still other ways to solve that problem?
T2
:
I could use the graph …
To some extent, from the lesson plan, T2 gave students a global strategy (table) to solve the task
based on his previous experiences, although there is no guarantee that students would continue to have
the same issues with the task (Figure 5). However, by giving the students the strategy, he inadvertently
is making the students dependent on him. Whereas, from the lesson plan, T1 is helping the students to
make decisions themselves (Figure 4). From the interview evidence, the two teachers have different
abilities in solving the task and differ on the approaches they offer to their students.
In relation to students’ possible mistakes and misconceptions, it seems that these teachers had
some ideas as to what their students would find difficult.
T1
:
The task has missing information, it should be more, and some students would think that. So
that they have not thought yet the possible ways to solve it. In average, students can directly
solve it with possible ways to do. They can find it directly.
T1
:
100. Maybe they thought that that’s the only think they know.
R
:
… So, they would answer it 100, possibly
T1
:
Yeah, possibly
T2
:
for those who did not understand, they would not know what 100 m rope is to with the
perimeter. So that the concept of perimeter, for those who understood, they already make it
but later they would not think the rectangles can be varied.
T2
:
Students would confuse the meaning of maximum, which is the largest, they have not
thought about it. So that students' thinking is not yet there. Their thinking is still circulated
on the perimeter not yet the perimeter to area and from area to find maximum area.
Teachers also have ways of responding to students’ mistakes, prompted by the researcher (Figure 7).
The researcher proposed a possible mistake by a student of which the shape looks like a rectangle 25 x
26,5.
Figure 7. A student's possible mistake proposed by the researcher
234 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
If faced with a student mistake that they have not thought of before, both teachers seemed to
engage thoughtfully with the scenario presented and sought ways of supporting students in addressing
the mistake. Rather than telling a student their answer was incorrect, they asked what the task wants,
and told them to check whether the shape is a rectangle or not.
R
:
If it happens if you see this (showing)
T1
:
I would ask students back to try it then you calculate it as what being asked to you
R
:
They have not yet known the result!
T1
Try, try it, by trialing they would know that it is different, this one is more, and that one is
like that, ....
R
:
T2, what if your students did this? what would you do?
T2
:
I would check it first, is it correct or not, the shape is a rectangle or not, they said that it is
not, so I asked whether the perimeter is 100 cm or not. So, by knowing that it is a rectangle,
the length would be equal, and the width would be equal (opposite sides), so that the
perimeter would be 100 cm...
In this study, the lesson plans facilitated an insight into teachers’ knowledge. In this case, it
showed teacher’s pedagogical knowledge as well as PCK. Lesson plans can contain rich information
on how the lesson is expected to be carried out. This is potential data to be used for assessing teachers’
knowledge. How the teachers organize and manages the classroom, task, and the discussion would be
depicted in the lesson plans. This resonates with Burns and Lash (1988) and Simon (1995) who argue
that in developing lesson plans, teachers integrate their knowledge, such as SMK and PCK. On the other
hand, experienced teachers may not use paper planning (written lesson plan) or just outlines as they
have knowledge of what will work best (Butt, 2008; Jones & Edwards, 2010). In addition teachers also
do mental planning for the lesson plans and the lesson plans are not written (Borko, Livingston, &
Shavelson, 1990). The dynamics of a classroom are very fluid, and a teacher must adjust to that fluidity
while following the plan. It is rare for a lesson to go exactly to plan. Yet, the execution of the lesson
plan determines the effectiveness of the lesson (Kow & Yeo, 2008). In Japanese lesson plans, they
contain more detailed instructions (Nakahara & Koyama, 2000) which shows more information about
teachers knowledge. In contrast, the two case of teachers in this study, have not yet shown detailed
instructions but more in general instruction.
Teachers have different ways of supporting students to solve tasks (Yeo, 2008). Students’
performance is more affected from teachers PCK (Baumert et al., 2010). However, SMK is basis
knowledge for teachers (Shulman, 1986; Turnuklu & Yesildere, 2007). It is not usual that teachers teach
‘something’ before mastering the subject matter thus reducing the possibility of teaching effectively
(Turnuklu & Yesildere, 2007). The teachers in this study were able to solve the task and had some ways
to respond to students when they made mistakes in solving the given task (possessing SMK and PCK).
However, these results are not generalizable. The limited sample was not chosen randomly and as these
teachers came from relatively developed areas in Java and have at least five years teaching experiences
they are not representatives of the wider Indonesian teaching population. Mathematics teachers in this
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 235
study might not show detail information on their lesson plans and have not fully been aware of
integrating PCK on developing their lesson plans. This study might not cover all mathematics teachers’
PCK profile in Yogyakarta or broadly in Indonesia. However, this study has provided an interesting
glimpse into one part of the very complex decision and knowledge processes that are involved in teacher
pedagogical knowledge.
CONCLUSION
This study indicates that it is possible to assess teachers' KCS of a specific topic through analysis
of the lesson plans when supported by interviews. There is evidence that these teachers had some
knowledge about student strategies and misconceptions about the area-perimeter of rectangle topic, and
that this knowledge was not necessarily fully integrated into their lesson plans. When prompted to think
about possible misconception, the teachers found that it was challenging. Understanding possible
misconceptions, making predictions and the anticipation of student responses would help teachers to be
better prepared in facing the situations during teaching. Developing problem solving skills and
autonomy among students requires teachers to stop providing a particular way (limiting students'
strategies) but rather provide an environment where students are able to choose strategies, to make
mistakes and to explore. Training for teachers could be more supportive in providing pedagogy that
promotes such an environment. Additionally, this study explored a rectangle topic, the result might vary
in different topics. Therefore, further investigation on different topic could be conducted. This study is
not generalizable as it used limited research subjects.
ACKNOWLEDGMENTS
The authors wish to thank to Ministry of Education of Republic of Indonesia; Planning and
Cooperation of Foreign Affairs for the scholarship. The authors also would like to thank SEAMEO
QITEP in Mathematics for its endless support.
REFERENCES
An, S., Kulm, G., & Wu, Z. (2004). The Pedagogical Content Knowledge of Middle School,
Mathematics Teachers in China and the U.S. Journal of Mathematics Teacher Education, 7, 145-
172. https://doi.org/10.1023/b:jmte.0000021943.35739.1c
Ball, D. L., Thames, M. H., & Phelps, G. (2008). Content knowledge for teaching: What makes it
special? Journal of Teacher Education, 59(5), 389-407.
https://doi.org/10.1177/0022487108324554
Baturo, A., & Nason, R. (1996). Student teachers’ subject matter knowledge within the domain of area
measurement. Educational Studies in Mathematics, 31, 235-268.
https://doi.org/10.1007/BF00376322
Baumert, J., & Kunter, M. (2013). The COACTIV model of teachers professional competence. In
Cognitive Activation in the Mathematics Classroom and Professional Competence of Teachers:
236 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
Results from the COACTIV Project (pp. 25-48). Boston: Springer. https://doi.org/10.1007/978-
1-4614-5149-5_2
Baumert, J., Kunter, M., Blum, W., Brunner, M., Voss, T., Jordan, A., … Tsai, Y. M. (2010). Teachers’
mathematical knowledge, cognitive activation in the classroom, and student progress. American
Educational Research Journal, 47(1), 133-180. https://doi.org/10.3102/0002831209345157
Borko, H., Livingston, C., & Shavelson, R. J. (1990). Teachers’ Thinking About Instruction. Remedial
and Special Education, 11(6), 40-49. https://doi.org/10.1177/074193259001100609
Burns, R. B., & Lash, A. A. (1988). Nine Seventh-Grade Teachers’ Knowledge and Planning of
Problem-Solving Instruction. The Elementary School Journal, 88(4), 369-386.
https://doi.org/10.1086/461545
Butt, G. (2008). Lesson Planning 3rd Edition. London: Bloomsbury Publishing.
Carle, S. M. (1993). Student held misconceptions regarding area and perimeter of rectangles. Critical
and Creative Thinking Capstones Collection, 46. http://scholarworks.umb.edu/cct_capstone/46
Cavanagh, M. (2007). Year 7 students’ understanding of area measurement. In K. Milton, H. Reeves,
& T. Spencer (Eds.), Annual Conference of the Mathematics Education Research Group of
Australasia (pp. 136–143). Adelaide: Australian Association of Mathematics Teachers.
Clark, C. M., & Peterson, P. L. (1986). Teachers’ thought process. Handbook of research on teaching.
New York: MacMillan
Clarke, D., Clarke, D., Roche, A., & Chan, M. C. E. (2015). Learning from Lessons: Studying the
Construction of Teacher Knowledge Catalysed by Purposefully-Designed Experimental
Mathematics Lessons. Proceedings of the 38
th
Annual Conference of the Mathematics Education
Research Group of Australasia (pp. 165-172). Sunshine Coast: MERGA
Denscombe, M. (2010). The Good Research Guide For Small Scale Research Projects. Berkshire: Open
University Press.
Fauskanger, J. (2015). Challenges in measuring teachers’ knowledge. Educational Studies in
Mathematics, 90, 57-73. https://doi.org/10.1007/s10649-015-9612-4
Hill, H. C., Ball, D. L., & Schilling, S. G. (2008). Unpacking pedagogical content knowledge:
Conceptualizing and measuring teachers’ topic-specific knowledge of students. Journal for
Research in Mathematics Education, 39(4), 372-400. https://www.jstor.org/stable/pdf/40539304
Hill, H. C., Rowan, B., & Ball, D. L. (2005). Effects of teachers’ mathematical knowledge for teaching
on student achievement. American Educational Research Journal, 42(2), 371-406.
https://doi.org/10.3102/00028312042002371
John, P. D. (2006). Lesson planning and the student teacher: Re-thinking the dominant model. Journal
of Curriculum Studies, 38(4), 483-498. https://doi.org/10.1080/00220270500363620
Jones, K., & Edwards, R. (2010). Planning for mathematics learning. In Learning to Teach Mathematics
in the Secondary School: A Companion to School Experience: 3rd Edition (pp. 79–100). London:
Routledge Taylor & Francis Group. https://doi.org/10.4324/9780203844120
Korkmaz, H. I., & Şahin, Ö. (2019). Preservice Preschool Teachers’ Pedagogical Content Knowledge
on Geometric Shapes in Terms of Children’s Mistakes. Journal of Research in Childhood
Education, 34(3), 385-405. https://doi.org/10.1080/02568543.2019.1701150
Kow, K., & Yeo, J. (2008). Teaching Area and Perimeter: Mathematics-Pedagogical-Content
Knowledge-in-Action. Proceedings of the 31st Annual Conference of the Mathematics Education
Yunianto, Prahmana, & Crisan, Indonesian Mathematics Teachers’ Knowledge of Content and Students 237
Research Group of Australasia.
Kristanto, Y. D., Panuluh, A. H., & Atmajati, E. D. (2020). Development and validation of a test
instrument to measure pre-service mathematics teachers’ content knowledge and pedagogical
content knowledge. Journal of Physics: Conference Series, 1470(1), 012008.
https://doi.org/10.1088/1742-6596/1470/1/012008
Lee, Y., Capraro, R. M., & Capraro, M. M. (2018). Mathematics Teachers’ Subject Matter Knowledge
and Pedagogical Content Knowledge in Problem Posing. International Electronic Journal of
Mathematics Education, 13(2), 75-90. https://doi.org/10.12973/iejme/2698
Nakahara, T., & Koyama, M. (2000). Proceedings of the Conference of the International Group for the
Psychology of Mathematics Education (PME)(24th, Hiroshima, Japan, July 23-27, 2000),
Volume 1.
Özerem, A. (2012). Misconceptions In Geometry And Suggested Solutions For Seventh Grade
Students. Procedia - Social and Behavioral Sciences, 55, 720-729.
https://doi.org/10.1016/j.sbspro.2012.09.557
Superfine, A. M. C. (2008). Planning for Mathematics Instruction: A Model of Experienced Teachers’
Planning Processes in the Context of a Reform Mathematics Curriculum. The Mathematics
Educator, 18(2), 11-22. https://ojs01.galib.uga.edu/tme/article/view/1925/1830
Setyaningrum, W., Mahmudi, A., & Murdanu. (2018). Pedagogical Content Knowledge of Mathematics
Pre-service Teachers: Do they know their students? Journal of Physics: Conference Series,
1097(1), 012098. https://doi.org/10.1088/1742-6596/1097/1/012098
Shulman, L. S. (1986). Those Who Understand: Knowledge Growth in Teaching. Educational
Researcher, 15(2), 4-14. https://doi.org/10.3102/0013189X015002004
Simon, M. A. (1995). Reconstructing Mathematics Pedagogy from a Constructivist Perspective.
Journal for Research in Mathematics Education, 26(2), 114-145. https://doi.org/10.2307/749205
Tatto, M. T., Peck, R., Schwille, J., Bankov, K., Senk, S. L., Rodriguez, M., Rowley, G. (2012).
Policy, Practice, and Readiness to Teach Primary and Secondary Mathematics in 17 Countries:
Findings from the IEA Teacher Education and Development Study in Mathematics (TEDS-M-
M). Amsterdam: International Association for the Evaluation of Educational Achievement.
Turnuklu, E., & Yesildere, S. (2007). The Pedagogical Content Knowledge in Mathematics: Pre-Service
Primary Mathematics Teachers’ Perspectives in Turkey. Issues in the Undergraduate
Mathematics Preparation of School Teachers, 1, 1-13.
Ünver, S. K., Özgür, Z., & Güzel, E. B. (2020). Investigating Preservice Mathematics Teachers’
Pedagogical Content Knowledge through Microteaching. REDIMAT-Journal of Research in
Mathematics Education, 9(1), 62–87. http://dx.doi.org/10.17583/redimat.2020.3353
Watson, A., Jones, K., & Pratt, D. (2013). Key Ideas in Teaching Mathematics: Research-based
Guidance for Ages 9-19 (1st ed.). Oxford: Oxford University Press.
White, A. L., Jaworski, B., Agudelo-Valderrama, C., & Gooya, Z. (2012). Teachers learning from
teachers. In Third International Handbook of Mathematics Education (pp. 393-430). New York:
Springer. https://doi.org/10.1007/978-1-4614-4684-2_13
Widodo, & Tamimudin, M. (2014). Three Training Strategies for Improving Mathematics Teacher
Competences in Indonesia. Electronic Proceedings of the 19th Asian Technology Conference in
Mathematics. Yogyakarta: Mathematics and Technology, LLC. Retrieved from
http://atcm.mathandtech.org/EP2014/index.html
238 Journal on Mathematics Education, Volume 12, No. 2, May 2021, pp. 223-238
Yeo, K. K. Y. (2008). Teaching Area and Perimeter: Mathematics-Pedagogical-Content Knowledge-
in-Action. Proceedings of the 31st Annual Conference of the Mathematics Education Research
Group of Australasia (pp. 621-627). Brisbane: The University of Queensland. Retrieved from
https://repository.nie.edu.sg/bitstream/10497/14397/1/MERGA-2008-621-YeoKK_a.pdf
Yin, R. K. (2014). Case study research: Design and methods. Thousand Oaks: SAGE Publications.
Yunianto, W. (2015). Supporting Students’ Understanding of Area Measurement Through Verknippen
Applet. Southeast Asian Mathematics Education Journal, 5(1), 73-82.
https://doi.org/10.46517/seamej.v5i1.34
Zacahros, K., & Chassapis, D. (2012). Teaching suggestions for the measurement of area in Elementary
School. Measurement tools and measurement strategies. Review of Science, Mathematics and
ICT Education, 6(2), 41–62. https://doi.org/10.26220/rev.1627