Serious video games (SVGs) are increasingly used as supplementary teaching tools for mathematics education. Several studies report their positive impact on student learning. However, these impacts are variable, and the success of the tools cannot be generalized or extended to all settings or disciplines without an in-depth look at the games themselves. Indeed, the impact of the tools depends on several factors, mainly, the quality of the games in terms of educational value and play value. This article summarizes the development of an SVG for learning fractions. It presents the theoretical considerations that guided the game design. The game was also tested in a classroom setting with primary students. An experimental protocol was used to measure the effects of the game on learning. The results of the study demonstrate a positive impact of the game on student learning. Use of the game also led to a significantly greater increase in learning compared to traditional instruction without use of the game. We examine these results and discuss the usefulness and impact of a game design model on SVG effectiveness.