This study aims to develop a social arithmetic learning design by integrating Islamic economic principles. Using various Islamic financial products as a context in mathematical tasks, we propose a hypothetical learning trajectory (HLT) to support the students' Islamic financial literacy (IFL) skills. We chose design research as the method to achieve the goal. However, we limit the discussion to a part of one phase, namely pilot experiments, of the three main phases of design research. This study involves six students at Islamic junior high school. The design consists of several activities that require students to solve mathematics-based Islamic financial literacy tasks. These tasks contain IFL knowledge, including money and shariah transaction, planning and managing finance using shariah product, risk, and reward of shariah finance product, and a landscape of shariah finance. We develop an instructional design by adapting the process domain of the OECD financial literacy by adjusting based on the principles of Islamic economics. In general, the stages of learning activities are identifying Islamic financial information, analyzing information in an Islamic financial context, and applying Islamic financial knowledge and understanding. At each of these stages, students are faced with problems that focus on each process domain. The results show that this design can bring out some fundamental mathematical capabilities and support the students' IFL. Furthermore, by infusing Islamic financial literacy in mathematics education, we get an opportunity to create a caring young generation on the development of Indonesian Islamic economics.