Strong foundational skills in basic arithmetic are essential for success in all areas of mathematics. Backward design, an approach where educators first define desired learning outcomes, allows them to tailor instruction and assessment to effectively achieve those learning  outcomes, McTighe and Wiggins (2005). Personalized learning complements this approach by adapting instruction to individual student readiness,interests, strengths and challenges, and prior knowledge, Bray (  (2016). Personalized learning also allows progression from teacher-generated to learner-generated. While both methods hold promise, large-scale implementation can be challenging due to teacher workload and the need for deep understanding of the approaches. This research investigates the effectiveness of backward design implemented with personalized learning strategies within the Elementary program in Sekolah High Scope Indonesia (SHSI). Specifically, it examines how this approach enhances students' achievement in basic arithmetic skills in three different themes i,e. Place value, Mathematical Operation and fractions within the Sekolah HighScope Indonesia.

Keywords: backward design, personalized learning, basic arithmetic skills, place value, mathematical operation and fractions