Abstract:
This research was a classroom action research aiming to investigate critical thinking and mathematical multiple representations grade 10 students through the Five Practices in designing and organizing learning activities. The target group included forty 10th grade students enrolled in the second semester of academic year 2017 at Sanpatong Wittayakom school in Chiang Mai province. The research instruments consisted of 8 mathematical lesson plans, post instruction reflecting notes, VDO recording, a four-item subjective test on critical thinking - that showed the discrimination ranged from 0.29 to 0.33, the difficulty ranged from 0.61 to 0.81 and the reliability was 0.74, a five-item subjective test on mathematical multiple representations - that showed the discrimination ranged from 0.20 to 0.67, the difficulty ranged from 0.53 to 0.85 and the reliability was 0.74. The research was conducted along the 4 steps of continuous 3 cycles of classroom action research composed of Plan, Act, Observe and Reflect. The researcher applied the Five Practices to design and organize learning activities was developed by Smith and Stein (2011) including Anticipating, Monitoring, Selecting, Sequencing and Connecting different thoughts of students through the whole class discussion led to the main purpose of the lesson. The data were analyzed in terms of mean, standard deviation and analytical description. The research findings reveal that the student had critical thinking at good level and mathematical multiple representations at good level.