ABSTRACT
The purpose of this study is to investigate the effect of problem-solving subject given
for the improvement of problem-solving skills and for teaching the problem-solving
strategies on primary preservice mathematics teachers’ ability to use the problemsolving
stages and on their mathematical thinking levels. The study is oriented to
descriptive survey, which is one of the quantitative research methods. In the study that
was conducted throughout 13 weeks (26 hours), the students were taught Polya’s
(1945) problem-solving stages, which are formed of four steps, and they were also the
problem-solving strategies in order to improve their problem-solving skills. In the
study, two problems developed by Posamentier and Krulik (1998) was used as data
collection tool, and “Mathematical Thinking Scale” developed by Ersoy (2012) was
used to determine whether the problem-solving lesson has an effect on mathematical
thinking. The findings obtained demonstrate that problem-solving subject has a positive
effect on preservice mathematics teachers’ improving their problem-solving skills, and
their skills of being able to choose and practise proper strategy. In addition, it was
concluded that problem-solving subject has a positive effect on mathematical thinking.