The effect of connecting, organizing, reflecting, and extending (core) instruction model by work card toward students’ mathematical problem-solving skill
The objective of this study was to observe the effect of Connecting, Organizing, Reflecting, and Extending (CORE) instruction model by work card toward students’ mathematical problem-solving skill. The research method was quasi-experiment using non-equivalent post-test only control group design. All classes in seventh grade become the population in SMP Negeri 1 Klari. Two-stage sampling technique, namely purposive sampling and cluster random sampling technique, were used to select VII-A as the experimental class who treated with the CORE instruction model by work card and VII-B as the control class who treated with direct instruction model. Students’ mathematical problem-solving skill was measured by the test which created based on problem-solving skill indicators. The hypothesis was tested using independent sample t-test with a significance value of 0.05. The result of the research shown that there was a significant difference between the experimental and the control class. There was t count = 4.693 > t table = 1.667, so H0 was rejected. This result was indicated that the average of the students’ problem-solving skill who using CORE instruction model by work card higher than the average of the students’ problem-solving skill who using conventional instruction model. Therefore, it can be concluded that CORE instruction model by work card affected students’ mathematical problem-solving skill.