This study aims to 1.investigate elementary school teachers''''
knowledge of fractions,knowledge of students'''' cognitions in
fractions and pedagogical knowledge; and 2.assess elementary
school teachers'''' understanding of these three components of
knowledge in fractions teaching. A sample of 136 elementary
school teachers took the pencil and paper test in this study.
Among these 136 subjects,33 were selected for interview in one
-to-one semi-structure way.The findings were as follows. 1.The
percentages of teachers'''' excellence understandings of those
three kinds knowledge were 33%、10%∼20%、13%∼30%
respectively. 2.Using the Principal Component Analysis,the
above mentioned knowledge can be decompounded into five
components:the knowledge of fractions, the knowledge of
fractions teaching materials,the ability to adjust
instructional design responsive to students'''' thinking patterns
,the knowledge of the hierarchy of students'''' understanding
fractions,as well as the knowledge of students'''' problem-solving
strategies.3.Using the Cluster Analysis,the above mentioned
five components can be categorized into two areas:the knowledge
of mathematics 、materials and methods ,as well as the
knowledge of students'''' mathematics learning. 7.4% of the
teachers excelled in both areas ;16.9% of the teachers excelled
in the knowledge of mathematics、materials and methods ; 26.5%
excelled in the knowledge of students'''' mathematics learning;
while approximately half of the teachers performed
unsatisfactorily in both areas.Taiwan in-service elementary
school teachers'''' understanding the knowledge in fraction
teachings is in a two-streams way. A model of the development
of elementary school teachers'''' mathematics teaching knowledge
within the context of Taiwan society is proposed according to
the results of this study.