摘要：Aspek pemahaman konsep matematis menjadi dasar utama siswa dalam menyelesaikan permasalahan matematika. Tujuan penelitian ini adalah memberikan deskripsi kemampuan pemahaman konsep matematis siswa kelas XI SMKN 1 Kudus dalam menyelesaikan soal komposisi fungsi. Indikator pemahaman matematis pada penelitian ini mengacu kriteria mengukur kemampuan pemahaman matematis Thompson, sehingga peneliti dapat mengukur dan mengetahui bagaimana kemampuan pemahaman matematis subjek penelitian. Penelitian menggunakan metode deskriptif kualitatif. Subjek dalam penelitian ini adalah 3 siswa kelas XI Tata Boga 3 dengan menggunakan teknik purposive sampling. Instrumen penelitian menggunakan 3 buah soal materi komposisi fungsi berupa tes tertulis berbentuk uraian yang telah disesuaikan dengan indikator pemahaman matematis yang digunakan. Setelah rangkaian proses analisis data dilakukan, hasil penelitian menunjukkan bahwa kemampuan pemahaman matematis dari ketiga subjek penelitian tergolong sangat tinggi berdasarkan tabel klasifikasi kemampuan pemahaman matematis, yaitu sebesar 86%. Secara garis besar, subjek menyelesaikan soal tes yang diberikan sesuai dengan aturan konsep, notasi, dan istilah dalam materi komposisi fungsi, meskipun masih terdapat kesalahan miskonsep yang dilakukan. The aspect of understanding mathematical concepts is the main basis for students in solving math problems. The purpose of this research is to describe the ability of students to understand mathematical concepts in class XI SMKN 1 Kudus in solving the composition of functions. Indicators of mathematical understanding in this study refer to the criteria for measuring Thompson's mathematical understanding so that researchers can measure and find out how the subject's mathematical understanding ability. This research used a qualitative descriptive method. The subjects in this study were 3 students of class XI “Tata Boga” 3 using the purposive sampling technique. The research instrument used 3 questions about the composition of the function in the form of a written test in the form of a description which has been adjusted to the indicators of mathematical understanding. After a series of data analysis processes were carried out, the results of this study indicated that the mathematical comprehension ability of the three research subjects was classified as very high based on the classification table of mathematical comprehension abilities, which was 86%. The subject completed the test questions given in accordance with the concept rules, notations, and terms in the function composition material, although there were still misconceptions that were made.
