Mathematics education has benefited from the increase in popularity of augmented reality (AR) technology. However, no game-based AR application has been developed specifically for prism topic. This paper aims to report PrismAR app that we have developed. It has interactive exercises and quiz and shows the prism's edges and vertices, in 2D and 3D views. This project aims to assist primary 3 students (9 years old) in developing their mathematical abilities and making prism mathematical concepts more interactive. An exploratory study design was used to evaluate the app with 20 students from a Malaysian school. We wanted to ascertain their degree of approval for the app's design, learning content, user interface, and interactivity with the augmented reality card game teachers. Overall, the assessment returned an average mean of 4.98, which was interpreted as 'highly acceptable.' The pre-test mean result is 12.6 (S.D. = 2.012), while the post-test mean result is 14.6 (S.D. = 1.789). The results indicate that using an augmented reality-based card game could be a successful method for increasing students' mathematics competence. This study serves as a call to action for potential developers and educators to improve AR integration in math education in the future.