Siswa merasa materi Matematika merupakan materi yang sangat sulit karena mempunyai banyak rumus yang sulit untuk dihafalkan, siswa merasa bosan saat pembelajaran Matematika, guru belum menggunakan model pembelajaran yang menarik sehingga menyebabkan kemampuan pemahaman konsep siswa rendah. Tujuan penelitian ini adalah untuk mengetahui penerapan model kooperatif tipe Numbered Head Together (NHT) efektif terhadap pemahaman konsep Matematika siswa kelas V SD Negeri Pandeanlamper 02 Semarang. Jenis penelitian ini adalah penelitian kuantitatif dalam bentuk Pre Eksperimental Design dengan desain penelitian One- Grup Pretest- Posttest Designs. Sampel penelitian adalah semua siswa-siswi kelas V SD Negeri Pandeanlamper 02 Semarang tahun ajaran 2017/2018 yang berjumlah 20 orang. Hasil penelitan diperoleh rata-rata nilai pretest 50,75 dan rata-rata nilai posttest 75,5. Berdasarkan hasil penelitian dan analisis data melalui perhitungan uji t diperoleh nilai  11,342 dan  = 2,09. Karena > , H_a diterima. Jadi dapat disimpulkan bahwa dengan diterapkan model kooperatif tipe Numbered Head Together (NHT) terdapat perbedaan yang signifikan terhadap kemampuan pemahaman konsep matematika siswa kelas V SD Negeri Pandeanlamper 02 Semarang.

Kata Kunci : Kooperatif, numbered head together, pemahaman konsep, Matematika.

Abstract: Students feel Mathematics material is a very difficult material because it has many formulas that are difficult to memorize, students feel bored while learning Mathematics, the teacher has not used an interesting learning model that causes the ability to understand the concept of low students. The purpose of this research is to know the application of cooperative model type Numbered Head Together (NHT) effective to understanding the concept of Mathematics class V student of SD Negeri Pandeanlamper 02 Semarang. This type of research is quantitative research in the form of Pre Experimental Design with One-Group Pretest-Posttest Designs research design. The sample of research is all students of class V SD Negeri Pandeanlamper 02 Semarang academic year 2017/2018 which amounted to 20 people. Research results obtained an average pretest value of 50.75 and an average posttest value of 75.5. Based on the results of research and data analysis through t test calculation obtained value t_hitung = 11.342 and t_tabel = 2.09. Because t_count> t_tabel, Ha accepted. So it can be concluded that by applying cooperative model type Numbered Head Together (NHT) there is a significant difference to the ability of understanding the concept of mathematics class V students of SD Negeri Pandeanlamper 02 Semarang.

Keywords: Cooperative, numbered head together, understanding concept,