Nugroho SA, Jailani J. The Effectiveness of Concrete Representational Abstract Approach (CRA) Approach and Problem Solving Approach on Mathematical Representation Ability at Elementary School . KSS [Internet]. 2019 Jun. 30 [cited 2025 Jul. 11];3(17):27–36. Available from: https://knepublishing.com/index.php/KnE-Social/article/view/4620