The purpose of this study is to investigate the effect of the material on the fourth grade primary school students' comprehension skill about fraction concept. Quasi-experimental research design including 44 students (22 experimental, 22 control group) were used. While the experimental group was taught with the materials based on the 7E model, the control group was taught with the existing textbook material. An open ended test including ten questions about fraction developed by the researchers and teachers was used as pre and post-test. Pre and post-test results were compared by using t-test in SPSS packet program and it was determined that there was a meaningful difference between experiment and control groups' success (t(42)=2.052, p=.046 <.05) about fraction. (C) 2010 Elsevier Ltd. All rights reserved.