ABSTRAKPelajaran matematika sering dianggap sulit dan kurang diminati maka diperlukan upaya untuk menjadikan pelajaran matematika menjadi menyenangkan dan diminati, yaitu salah satunya dengan menggunakan pendekatan pembelajaran. Hal ini untuk meningkatkan minat dan motivasi yang juga berdampak dengan hasil belajar siswa dan juga meningkatkan kualitas pembelajaran. Tujuan Penelitian ini untuk mengetahui peningkatan hasil belajar siswa dengan menggunakan pendekatan pembelajaran STEAM berbasis PJBL. Penelitian ini termasuk penelitian tindakan kelas yang meneliti siswa kelas 1C SD Negeri 98 Palembang yang berjumlah 31 orang. Penelitian ini dilakukan sebanyak 2 siklus. Setiap siklus terdiri dari 4 tahapan, yaitu perencanaan, tindakan, pengamatan, dan refleksi. Instrumen yang digunakan yaitu tes dan lembar observasi. Berdasarkan hasil penelitian, dapat diperoleh nilai rerata matematika mengalami peningkatan di mana pada siklus 1 siswa yang mencapai nilai KKM sebanyak 16 siswa atau sebesar 52% sedangkan 15 siswa belum mencapai ketuntasan atau sebesar 48 % sehingga peneliti melanjutkan penelitian ke siklus 2. Pada siklus 2, hasil belajar siswa mengalami peningkatan yaitu sebesar 100 % siswa sudah mencapai ketuntasan. Untuk rata-rata nilai siswa juga meningkat di mana pada siklus 1 sebesar 62,6 dan pada siklus 2 sebesar 92,3 yang artinya sudah mencapai di atas KKM sehingga diperoleh kesimpulan bahwa penggunaan pendekatan STEAM dapat meningkatkan hasil belajar siswa pada materi mengenal bangun ruang kubus dan balok.ABSRACTMathematics was often diffiult and less desirable, efforts are needed to make mathematics fun and desirable, one of which is by using a learning approach. This is to increase interest and motivation which also has an impact on student learning outcomes and also improves the quality of learning. The study aims to determine the the improvement of student learning outcomes using the STEAM learning approach. This research included classroom action research that examined 31 grade 1C students of SD Negeri 98 Palembang. This study was conducted as many as 2 cycles. Each cycle consists of 4 stages, namely planning, action, observation, and reflection. The instruments used are tests and observation sheets. Based on the results of the study, it can be obtained that the average score of mathematics has increased where in cycle 1 students who achieve the minimum completeness criteria (KKM) scores as much as 16 person or as large as 52% while 15 students have not reached completion or as large as 48 % so the researcher continues the research to cycle 2. In cycle 2, student learning outcomes have increased by 100 % of students have reached completion. For the average student scores also increased where in cycle 1 by 62,6 and on cycle 2 amounting to 92,3 which means that it has reached above the minimum completeness criteria so that it is concluded that the use of the STEAM approach can improve student learning outcomes on knowing cube and block space building materials.ABSRACTMathematics was often diffiult and less desirable, efforts are needed to make mathematics fun and desirable, one of which is by using a learning approach. This is to increase interest and motivation which also has an impact on student learning outcomes and also improves the quality of learning. The study aims to determine the the improvement of student learning outcomes using the STEAM learning approach by PJBL based. This research included classroom action research that examined 31 grade 1C students of SD Negeri 98 Palembang. This study was conducted as many as 2 cycles. Each cycle consists of 4 stages, namely planning, action, observation, and reflection. The instruments used are tests and observation sheets. Based on the results of the study, it can be obtained that the average score of mathematics has increased where in cycle 1 students who achieve of KKM scores as much as 16 person or as large as 52% while 15 students have not reached completion or as large as 48 % so the researcher continues the research to cycle 2. In cycle 2, student learning outcomes have increased by 100 % of students have reached completion. For the average student scores also increased where in cycle 1 by 62,6 and on cycle 2 amounting to 92,3 which means that it has reached above the KKM so that it is concluded that the use of the STEAM approach by PJBL based can improve student learning outcomes on knowing cube and block space building materials.