In conducting students' learning activities that do not always work, there are often things that cause failure. The study aims to describe the difficulties students have experienced and to study the mistakes of the students in working on the tests in mathematics learning on the set subject. This type of research is a qualitative descriptive with a case study approach. Data collection techniques with problem instruments, interviews, and documentation. The legitimacy of data using technique triangulation. Data analysis through the data reduction phase, data presentation, and withdrawal of conclusions. The research was conducted with the subject of his research 30 students. The results showed that the type of difficulties experienced by students in the form of 1) difficulty in understanding the problem is the inability of the students to interpret the mathematical symbols on the subject of the set, 2) difficulty transforming that is the inability of students determining the set formula, 3) difficulty in the completion process is that students are not able to perform binary counting operations to solve the set problem. Then it can be concluded the types of difficulty learning mathematics that students experience in the subject of the association can be classified into 3 types, namely difficulty in understanding the problem, difficulty transforming the problem, and difficulty solving problems.

Sampai saat ini, perkembangan teknologi informasi telah merambah ke berbagai sektor termasuk di sektor kesehatan yang mampu membantu dalam mendiagnosa penyakit melalui gejala yang diberikan serta dapat memberikan solusi penanganan penyakit. Salah satu penyakit yang dapat dilakukan diagnosa dengan adanya perkembangan teknologi komputer adalah penyakit gusi. Penyakit gusi adalah penyakit infeksi yang menyerang pada jaringan di sekitar gigi. Kondisi ini merupakan penyebab utama dari gigi yang lepas pada orang dewasa. Perawatan gigi merupakan salah satu usaha penjagaan untuk mencegah kerusakan gigi dan penyakit gusi. Penyakit gusi dapat menyerang siapa saja baik menyerang bayi, balita, remaja bahkan menyerang orang dewasa. Menurut jurnal penelitian dari Mubasyiroh, dan Andayasari (2017:141) berpendapat bahwa Penyakit gigi dapat berupa kerusakan gigi (karies) dan penyakit gusi. Penyakit gigi dan mulut (termasuk karies dan penyakit periodontal) merupakan masalah yang cukup tinggi yang dikeluhkan oleh masyarakat. Adapun cabang ilmu komputer yang dapat melakukan diagnosa untuk mengetahui penyakit gusi adalah sistem pakar.Berdasarkan hasil pembahasan diatas, maka didapatkan jawaban B1, B2, B3 sampai dengan B9 gejala penyakit berdasarkan pilihan pertanyaan yang dipilih, itu menandakan, bahwa sistem pakar dengan metode forward chaining dapat mengatasi penyakit gusi dengan tingkat kepercayaan 89%

In the 21st century, the ability to be mastered by students is increasingly complex, such as the ability of critical thinking, creative thinking skills, communication skills, ability to cooperate, as well as ability in reasoning. The ability of reasoning in students is crucial to learn and develop. The reasoned ability is not only needed when studying mathematics but is indispensable when determining decisions in life. The instrument in this study is how the mathematical reasoning process of students is low, moderate and high on the subject matter of three dimensions. The study aims to know students' learning difficulties relating to the students' mathematical reasoning ability on surface area material and the volume of three-dimensional space. This research is a qualitative descriptive study with a case study approach. The subject of this study involved 30 students. The instrument in this research is a mathematical reasoning ability test. The results showed that 40% of students had high reasoning ability, 40% of students had moderate reasoning ability, and 20% had low reasoning ability. Students with high reasoning ability have no significant difficulty in completing the instrument in this study, students with reasoning ability are having difficulty in calculating and interpreting the intent of the question, and students with low reasoning ability have difficulty in drafting a completion plan. The study concluded that the students' reasoning ability on the three-dimensional material belongs to the medium category.

Analisis bangunan bersejarah makam Kyai Semar di Magelang memiliki tujuan untuk mengetahui sejarah makam Kyai Semar serta menganalisis pendekatan geometri pada volume bangun makam Kyai Semar. Pada penelitian ini, metode yang digunakan berupa penelitian deskriptif dengan pendekatan kualitatif dengan teknik pengumpulan data melalui wawancara, dokumentasi, dan observasi secara langsung di makam Kyai Semar. Dari penelitian ini diperoleh hasil yaitu makam Eyang Ismoyo Jati atau makam Kyai Semar adalah makam kedua setelah makam Kyai Sepanjang. Kyai Semar adalah pamomong Tanah Jawa. Makam tersebut direnovasi pada hari Kamis sekitar bulan Juni tahun 2006. Makam yang terletak di puncak Gunung Tidar, Magersari, Magelang tersebut berbentuk Tumpeng Jejeg Sejati yang di dasar tumpeng dikelilingi (disabuki) dengan tulisan jawa Ha Na Ca Ra Ka dan di puncaknya ditusuk dengan janur kuning. Makam tersebut dikelilingi dengan pagar tembok berbentuk balok yang setiap sisinya terdapat naga. Keseluruhan makam Kyai Semar mulai dari atas sampai bawah yang jika ditinjau dari pendekatan geometri makam ini merupakan gabungan dua bangun ruang, yaitu bangun kerucut dan bangun balok. Bangun balok pada makam Kyai Semar memiliki ukuran panjang dan lebar masing-masing sebesar 9 meter serta memiliki tinggi sekitar 1,5 meter, sedangkan pada bangun kerucut memiliki ukuran diameter dan tinggi masing-masing sebesar 9 meter serta apotema 10,06 meter. Dengan demikian, volume dari bangun makam Kyai Semar adalah 313 meter kubik.

By introducing Indonesian batik motifs, we know that the island of Sumatra, especially Bengkulu and Jambi provinces, has a distinctive batik called Basurek batik. This research aims to classify the two batik motifs using the Support Vector Machine (SVM) algorithm. First, we extract the image of the batik motif with a pre trained VGG-16 model and then use them as a dataset for the SVM classification process. The classification process itself uses linear, polynomial, and sigmoid kernels. We divided the data 90:10 and used 10-fold cross-validation to analyze each training and testing data classification result. The results of this study are the highest values of accuracy, precision, and recall of 76.4%, 76.5%, and 76.4% produced by the linear kernel for the training data classification. For the testing data classification, both the linear and polynomial kernels generate the best accuracy, precision, and recall values of 87.5%, 90%, and 85.5%. On average, incorporating the training and testing classification results, we found that the linear kernel is the best function for classifying the Basurek batik motif using the collected images from the internet.