Teaching the Concept of Unit in Measurement Interpretation of Rational Numbers

Abstract

This study investigated middle school students understanding of unit and unitization concepts in
measurement interpretations of rational numbers using the number line as a tool. Fifty-six seventh-grade students
were pretested and five consecutive whole-class teaching experiments were developed and administered based on
pretest results. Five students were later chosen for semi-structured clinical interviews, based on their conceptions of
unit and unitization. Students’ reasoning was induced from the analysis of pre- and post-tests, observations of
classroom teaching episodes, videotapes of interviews, and transcriptions and photographs of student artifacts.
Results suggested that unit identification created difficulty for students in locating rational numbers on number lines