The journal invites original research articles and not simultaneously submitted to another journal or conference. The whole spectrum of research in mathematics education are welcome, which includes, but is not limited to the following topics: Realistic Mathematics Education (RME) Realistic Mathematics Education (RME) is a teaching and learning theory in mathematics education that was first introduced and developed by Freudenthal. Two of his important points of views are mathematics must be connected to reality and mathematics as human activity. RME is implemented following three principles, they are: (1) guided reinvention and progressive mathematizing, (2) didactical phenomenology, and (3) self-developed model. Furthermore, the practice of RME also has its own characteristics, they are: (1) phenomenological exploration or the use of contexts, (2) the use of models or bridging by vertical instruments, (3) the use of students own productions and constructions or students contribution, (4) the interactive character of the teaching process or interactivity, and (5) the intertwining of various learning strands. A paper is eligible to be included in this topic if the paper accommodates these three principles and these five characteristics. Design Research in Mathematics Education Educational design research is perceived as the systematic study of designing, developing and evaluating educational interventions (programs, teaching-learning strategies and materials, products, systems) as solutions to such problems. It also aims at advancing our knowledge about the characteristics of these interventions and the processes to design and develop them. Authors could submit their work, either a validation study or a development study in mathematics education, with a comprehensive description and analysis of every stage. Mathematics Ability Mathematics ability refers to the ability (a human construct) to obtain, to process, and to retain mathematical information (cognitive) and to solve mathematics problem (pragmatic). To maintain the focus of this journal, the scope of mathematics ability includes the following abilities: reasoning, connection, communication, representation, and problem-solving. A paper is eligible for this topic if it comprehensively discusses those abilities.