Abstract:

This study aims to define the types of reasoning employed by students in proportional and non-proportional cases. Descriptive research has been used to describe or portray the  properties  of  a  situation  or  phenomenon  accurately.  A  total  of  146  midde  school students,  including  70  fifth  grade  students,  45  sixth  grade  students  and  31  seventh grade  students  participated  in  the  study.  In  the  study,  a  two-tier  proportional reasoning  diagnostic  test  developed  by  Hilton,  Hilton,  Dole  and  Goos  (2013)  was translated into Turkish and used as the data collection tool. The findings were analyzed by  means  of  descriptive  statistics  methods.  The  study  concluded  that  most  of  the students developed misconceptions since they utilized additive or absolute reasoning strategies  instead  of  multiplicative  reasoning  strategies.  Moreover,  the  students mistakenly  employed  additive  reasoning  strategies  by  acting  as  if  there  was  an absolute change entailing the use of proportional reasoning and failed in determining when to use proportional reasoning strategies. Proportional reasoning is essential for many  different  disciplines  as  well  as  for  mathematics.  For  that  reason,  this  study suggests that teachers identify the strategies inaccurately used by students and prepare a course plan according to their conceptual and operational deficiencies. 

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