Penelitian ini bertujuan untuk:(1) meningkatkan kemampuan komunikasi, kemampuan berpikir reflektif, dan kemampuan berpikir kreatif siswa SMA,(2) mengetahui respon siswa terhadap pembelajaran matematika dengan pendekatan open-ended. Penelitian ini merupakan studi eksperiment dengan desain penelitian bentuk pretest dan posttest yang dilaksanakan di Kota dan Kabupaten Bandung, dengan subyek utama siswa SMA dari beberapa sekolah. Penelitian ini menggunakan beberapa jenis instrumen yaitu tes tulis, observasi, angket, jurnal siswa, dan pedoman wawancara. Data dianalisis secara kuantitatif dan kualitatif. Berdasarkan hasil penelitian diperoleh kesimpulan bahwa;(1) kemampuan komunikasi matematik siswa yang mengikuti pembelajaran dengan menggunakan pendekatan open-ended lebih meningkat daripada siswa yang mengikuti pembelajaran matematika dengan model ekspositori,(2) terdapat peningkatan kemampuan berpikir reflektif siswa yang memperoleh pembelajaran matematika dengan menggunakan pendekatan openended melalui model pembelajaran kooperatif. Berdasarkan hasil perhitungan, peningkatan yang terjadi tergolong dalam kategori sedang dengan perolehan rata-rata sebesar 0, 31,(3) peningkatan kemampuan berpikir kreatif siswa yang mendapatkan pembelajaran pemecahan masalah matematis terbuka (open-ended) lebih baik dibandingkan dengan siswa yang mendapatkan pembelajaran ekspositori,(4) respon siswa terhadap pembelajaran matematika dengan pendekatan open-ended positif.

ABSTRACT

The purpose of this researh are:(1) to increase mathematical commucation ability, reflective thinking ability, and creative thinking ability of students of Senior High School,(2) to know response of students towards mathematics learning with the open-ended approach. This study is an experiment study with pretest and posttest group design forms of research conducted in the City and County of Bandung, with the main subject of senior high school students from several schools. This study used several types of instruments are written test, observation sheet, questionnaire, journal, and interview guideline. The data is analyzed quantitatively and qualitatively. Based on research results it is concluded that,(1) communication ability of the students who followed the teaching of mathematics using the open-ended approach is better than communication ability of the students who followed the teaching of mathematics with expository model,(2) there is an increase reflective thinking ability on the students who obtained a mathematics lesson using the approach of the open-ended through cooperative learning model. Based on calculations, the increase occurring in the medium category pertained to the acquisition by an average of 0.31,(3) increasing the ability of creative thinking of students who have learning mathematical problem solving is open (open-ended) better than students who have learning expository,(4) response of students towards mathematics learning with the open-ended approach is positive.