Learning algebra can be challenging for students due to its abstract nature. Contextualizing algebraic concepts through storytelling and gamification can enhance comprehension and increase engagement. This study presents the development and evaluation of the Digital Algebra Game (DAG), an interactive prototype designed using digital game-based learning and digital storytelling frameworks. A mixed-method approach was employed to assess the game's educational impact and usability, involving pre- and post-tests, semi-structured interviews, and user experience questionnaires with 20 children aged 9 to 11. The findings reveal three key contributions: (1) DAG supports children's understanding of algebraic concepts by making them more concrete, contextual, and interactive; (2) Usability evaluation identified specific areas for design improvement to better support learning; and (3) The integration of pedagogical principles into game design highlights the potential of digital educational games to foster meaningful mathematical understanding.