This Performance assessment instruments to measure 21st century competencies, namely 4C (critical thinking, creativity, collabor). The instrument can be used as a measuring tool in determining the achievement of competencies expected in the 21st centuryation, and communication). Critical thinking, creativity, collaboration, and communication competence can be integrated in STEM learning from an early age. The purpose of this study is to develop a 4C performance assessment instrument that can be used for measuring tools in STEM-based learning in elementary schools. The method that has been used is Educational Design Research (EDR) according to Mc Kenney and Reaves through three stages namely Analysis and Exploration, Design and Construction, and Evaluation and Reflection. This study included 11 observers who observed 5 students as samples. Data collection was conducted by means of interviews, expert judgment and questionnaire entries. The results of the study are instruments of student performance assessment. This instrument is used as an assessment tool that can be used to assess student performance that includes criteria, achievement scores, and descriptions of achievement scores. This development of performance appraisal instruments can be used as a form of assessment because most of the results show Asymp. Sig <0.05 which is categorized as alignment. This 4C performance assessment instrument is expected to be used in general in conducting performance assessments that measure 21st century competencies in STEM learning.

As a country with the most ethnic, cultural, and linguistic backgrounds globally, Indonesia has great potential for the development of ethnomathematics studies. Among those ethnic groups, Sundanese ethnic group and culture is the second-largest after the Javanese ethnic group and culture, making it interesting to study because it has rich cultural elements that can be integrated into the mathematics curriculum in schools. This article explores the development of research on ethnomathematics based on Sundanese culture, including those which are based on the study's scope, the integration of Sundanese ethnomathematics into the school curriculum, and mathematics learning. Based on the investigation, there has been no systematic literature review on Sundanese ethnomatematics. The research was conducted using the Systematic Literature Review method with the PRISMA protocol. The results showed that there were various kinds of research on Sundanese ethnomathematics. There were various kinds of study on Sundanese ethnomathematics integration into mathematics curriculum and teaching using five model categories. The results also showed that RME, CTL and PBL were the most widely used teaching approaches for learning Sundanese ethnomathematics. However, most of Sundanese ethnomathematics teaching uses a special approach  that varies, developing teaching material, teaching media and using the context of traditional games.

This research aims to develop the design principles of STEM learning in elementary schools using educational design research. In this study, five STEM learning projects have been designed for fourth grade elementary students. This article presents the results of analysis and exploration as the first phase of educational design research that includes initial orientation, literature review, field-based investigation, site visit, professional meeting and networking. The analysis and exploration phase was carried out through the methods: interview, focus group discussion, observation and document analysis with the strategies: policy synthesis strategy, portrait field, perception pool and SWOT analysis. The results confirm that the integration of STEM learning into the Indonesia elementary curriculum is very appropriate to be implemented to support the development of 21st century skills of elementary school students. Products resulting from this phase are problem definitions, long-range goals, partial design requirements and initial design requirements.

This research comes from an idea that algebraic thinking is one of the important things in learning mathematics for elementary school students. Algebraic thinking ability is a transitional process from arithmetic learning to algebraic learning. Students in elementary school must have aquired this ability as some prerequisite for advanced mathematics (at the level of junior high school). Aside from that, the Algebraic Thinking ability requires students to solve mathematical problems. The main purpose of this research is to describe students' algebraic thinking ability based upon algebraic-thinking characteristics, knowing the learning trajectory of learning barriers to overcome these obstacles. Therefore, the researcher conducted the research by utilizing a descriptive research method. The data were collected by means of test, interview and questionnaire on students in upper grades of elementary school located in urban areas, mid areas, also transitional regions. Based on the analysis of the results of algebraic thinking ability instrument test from 78 students, and having compared with the indicators of algebraic thinking in upper grades of elementary school in Indonesia, it shows that algebraic thinking skills of upper elementary grades in Indonesia are seemingly less good. In addition, researchers classify the barriers of algebraic thinking into three types, namely ontogenic obstacle, didactic obstacle, and epistemological obstacle, therefore with the data, the researcher generates hypothetical learning trajectory to cope with the obstacles of algebraic thinking. Learning trajectory as a result of this study will be developed as algebraic thinking design learning.

Pembelajran IPS di sekolah dasar mencakup konsep-konsep yang abstrak seperti waktu, perubahan, kesinambungan, ritual, arah mata angin, akulturasi, kekuasaan, demokras dan niai-nilai. Media merupakan salah satu solusi untuk mengkonkritkan materi dan konsep yang abstrak dalam pembelajaran. Namun faktanya darihasil studi pendahuan ke tiga sekolah dasar di Kota Tasikmalaya yaitu SDN 1 Urug, SDN Mugarsari dan SDN Citapen diperoleh informasi terkait penggunaan media yang hanya sebatas pada media praktis. Berdasarkan hal tersebut, peneliti bermaksud melakukan penelitian pengembangan yang pada akhirnya dihasilkan produk berupa media pembelajaran puzzle berbasis tangram dalam pembelajaran IPS tentang mengenal tokoh proklamasi dengan menggunakan metode penelitian design based research model reeves. Subjek penelitian ini adalah guru dan peserta didik kelas V yang berjumlah 17 orang di SDN 1 Urug dan 19 orang di SDN Mugarsari. Pengumpulan data dilakukan dengan teknik wawancara,observasi dan kuesioner. Rancangan produk dinyatakan layak diuji coba berdasarkan hasil validasi ahli.Kegiatan uji coba dilakukan sebanyak dua kali di sekolah yang berbeda. Uji coba yang pertama dilakukan di SDN 1 Urug dan uji coba dua di SDN Mugarsari. Hasil uji coba menunjukan bahwa media yang dikembangkan telah baik dan dapat menjadi solusi bagi guru dalam menyampaikan materi pembelajaran. Produk akhir berupa media pembelajaran puzzle  puzzle berbasis tangram dalam pembelajaran IPS tentang mengenal tokoh proklamasi untuk kelas IV Sekolah Dasar yang dilengkapi dengan buku panduan penggunaan.