Using the RME Principles to Support Students Problem Solving be HOTS Oriented Sabina Ndiung {punyaku79@gmail.com} Universitas Katolik Indonesia Santu Paulus Ruteng 1 Abstract. This study aims to explain the RME approach for improving elementary school students' problem-solving ability be HOTS Oriented. This analysis is an experimental study that employs a pretest-posttest control group design. The study sample consisted of 41 grade V SDK Wae Mata. The data testing technique employed a five-item test with a reliability coefficient of 0.83 in the high category. The data analysis technique used in this study was parametric statistical techniques with an independent t-test preceded by a test for data normality and variant homogeneity using the SPSS 23.0. This is indicated by the value of tobs= 38.071 > from tcrv = 2. 021 with a significance of 0.001< 0.05. This result indicates that implementing the RME approach, as demonstrated by the RME principles, could support students to problem-solving ability be HOTS Oriented Keywords: Mathematics, Problem-solving ability, RME principles 1 Introduction Today's education must be oriented toward a twenty-first-century education, enabling educators to prepare students with the "four Cs," critical thinking and problem-solving communication and collaboration, and creativity and innovation. Educators need to prepare students with the "four Cs," or critical thinking and problem-solving communication and collaboration, and creativity and innovation. New standards are required to ensure that students possess the competencies needed to resolve the second theme, namely learning and innovation skills. These skills include (1) critical thinking and problem-solving, in which students can apply inductive or deductive reasoning to a variety of situations; use a systematic way of thinking; and make decisions and solve problems (2) communication and collaboration, where students can communicate clearly and collaborate with other group members; and (3) creativity and innovation, that students can think creatively, work creatively and create innovations [1], [2]. Improving education's quality can be accomplished by enhancing both the quality of learning and the quality of the assessment system. The basic concept of assessment developed refers to the latest revision in the 2013 Curriculum, which center on improvements to the content standards and assessment standards. The content standard is designed to develop students' ability to think critically and analytically following international standards, which is done by reducing irrelevant material and the enhancement and expansion of relevant material for students. In contrast, the assessment standard is implemented through the adaptation of international standard assessment models gradually. Assessment of learning outcomes focuses more on higher-order thinking skills [3]. ICEHHA 2021, June 03-05, Flores, Indonesia Copyright © 2021 EAI DOI 10.4108/eai.3-6-2021.2310654