As a medium for learning, digital games provide promising possibilities to motivate and engage students in subject learning. In this study, a game-based learning system, My-Pet-My-Quest, is developed to support pupils’ math learning. This is due to the fact that most students in Taiwan have relatively lower positive attitude towards math learning, even though their math performance is prominent. To this end, a three-tire framework is proposed to guide the design of the My-Pet-My-Quest system. A quasi-experiment was conducted to examine the influence of game quests on pupils’ enjoyment and goalpursuing in math learning. The results revealed that game quests were favored by students in terms of enjoyment, goal orientation, and goal intensity. Possible reasons for these results and a discussion of related issues are presented in this paper.