In an effort to improve students' mathematical
reasoning there are Permana and Sumarmo (2007)
stating that reasoning is a process of thinking in the
process of drawing conclusions. Broadly speaking
there are two types of reasoning, namely the
inductive reasoning also called induction and
deductive reasoning also called deduction. The
similarity between deduction and induction is that
both are structured arguments, composed of several
premises and one conclusion. The difference
between deduction and induction on the basis of the
inference conclusion and also the characteristics of
the conclusions it derives.
Besides cognitive, there are things that are also
very important to note by a teacher with regard to
the development of their students’ attitude to
mathematics itself. Attitude is the part that also
determines the success of students in the learning
process. According to the authors thing important to
note is the self-efficacy of students. Research during
the past 30 years has revealed a positive relationship
between self-efficacy beliefs and academic
performance and persistence (Martin & Marsh,
2006; Multon, Brown, & Lent, 1991; Skaalvik &
Skaalvik, 2004). Self-efficacy is in practice
synonymous with "self-belief", although "self-
belief" is a non-descriptive term (Bandura, 1997),
which refers to the power of belief, for example one
can be very confident, but ultimately fail. Self-
efficacy is defined as a person's judgment about his
or her ability to attain desired or determined
performance levels that will influence the
subsequent action (Bandura, 1997). Mathematics
self-efficacy positively impacts academic
achievement by allowing one to use cognitive
strategies, enhancing the belief in successful
completion of tasks, and encouraging one to come
up with alternative solutions for the problem in hand
(Stevens, Olivarez, Lan, & Runnels, 2004). Studies
shows that students with high-perceived self-
efficacy make more effort to accomplish a task and
are more persistent in the face of difficulties (Aşkar
& Umay, 2001). Hackett & Betz (1989) report that
students with higher mathematics self-efficacy have
lower mathematics anxiety and place more value on
mathematics.
Pintrich and De Groot (Rahmi, Nadia, Hasibah,
& Hidayat, 2017) found that students who believed
they could perform academic tasks using cognitive
and meta-cognitive strategies are more and still
doing better than unbelieving students. Self-efficacy
makes a difference in the way people act, as a
follow-up of feelings and thoughts. People who
believe they can do something that has the potential
to transform environmental events are more likely to
act and more likely to succeed than those with low
self-efficacy. Behavior is influenced by the extent to
which a person believes to perform the actions
required by the particular situation.
Based on observations made at SMA Prayatna
Medan, it is known that the ability of reasoning and
self-efficacy owned by students in this high school is
still low. This can be seen from the only few
students who are able to make allegations, perform
mathematical manipulations, give reasons for the
answers, present the results of group work and draw
conclusions from a given mathematical problem.
According to the results of interviews conducted by
the authors to several mathematics teachers and
some students at Prayatna High School Medan, it is
found that the factors that cause the low of reasoning
ability and self-efficacy of students are students are
deficient in understanding the mathematical
concepts such as not precisely solving a problem
provided by teachers, also less using the reasoning
on patterns and characteristic as explaining the
mathematical ideas and statements, lacking the
ability to design mathematical models and
interpreting the solutions obtained. The lacks of
interest in students' learning mathematics are caused
by the lessons and motivations provided by teachers,
difficulty to accept, their absence of interest in
mathematics, lack of facilities and infrastructure,
fear of the math teacher and all of this cause the
students not to be active to ask if there is a lesson
that students do not understand.
Based on the above problems a solution is
needed to improve students’ reasoning and self-
efficacy by providing treatment using a problem-
based model. Borrow (Huda, 2014) defines that
problem-based learning (PBL) is the lessons learned
through the process towards understanding the
resolution of a problem. The problem is found first
in the learning process. Hudojo (in Gunantara, et al,
2014) state that Problem Based Learning (PBL) is a
process taken by a person to solve the problem they
face until the problem is no longer a problem for
them. Also, Sudarman (2014) says the PBL is an
approach to learning that uses real-world problems
as a context for students to learn about critical
thinking and problem-solving skills, as well as to
acquire knowledge and essential concept of the
subject matter.
So based on the explanation above an attempt to
develop students' reasoning and self-efficacy skills,
is done so the formulation of problems in this study
are: (1) Is the reasoning ability of students using
Problem Based Learning model is better than the