Abstract:
The purposes of this research were to study the concepts on fraction and to promote mathematical reasoning abilities of 7th grade students using the Five Practices in designing and organizing learning activities. The target group was consisted of forty-seven 7th grade students enrolled in the second semester of 2017 academic year at Wattanothaipayap School, Chiang Mai province. The research instruments included 9 mathematical lesson plans emphasizing fraction concepts and mathematical reasoning, a nine-item subjective test on fraction concepts - that showed the difficulty ranged from 0.39 to 0.63, the discrimination ranged from 0.33 to 0.63, and the reliability was 0.85, a 11-item subjective test on mathematical reasoning abilities - that showed the difficulty ranged from 0.45 to 0.69, the discrimination ranged from 0.41 to 0.85, and the reliability was 0.89. The researcher utilized the Five Practices developed by Smith and Stein (2011) in designing and organizing learning activities including Anticipating, Monitoring, Selecting, Sequencing, and Connecting students ideas to the concept of mathematics. The data were analyzed in terms of mean, standard deviation and analytical description. The research findings revealed that the student had acquired the concepts on fraction at good level and mathematical reasoning abilities at good level.