(SIMILARITY) MENINGKATKAN KEMAMPUAN BERFIKIR KREATIF DALAM PEMECAHAN MASALAH BARISAN DAN DERET GEOMETRI DENGAN METODE OPEN ENDED

Classroom action research aims to improve the creative thinking skills of class XI SMA Muhammadiyah 1 Rambipuji in solving mathematical problems with geometrical lines and series. The data collection instruments were tests, interviews, and observations. Techniques, reduction of data presentation, and withdrawal are steps of analyzing data. Two students in each group became the research subjects. The results of this study indicate that: group one is creative in solving problems at number one but number two still follows the formula in the book and group one has reached how to solve problems, namely being able to understand problems, plan solutions, solve problems according to plan and re-check. . Group two in question number one still follows the formula given by the teacher but in question number number two they have been creative in solving problems, and group two has reached the requirements of problem solving, namely being able to understand the problem. Groups three in numbers one and two have been creative in solving problems of sequences and series and group two have met all problem-solving indicators, namely being able to understand the problem. In conclusion, groups one, two, three have been thinking creatively. Keywords : creative thinking, open ended, problem solving