Serious games are increasingly being used in education. The study examines the learning outcomes of a pilot project which lasted for 4 weeks and used a 3D serious game for teaching Mathematics to first-grade students. The game was developed using Microsoft's Kodu Game Lab. Mathematics was selected as a teaching subject because of the difficulties students have in understanding basic math concepts. The learning outcomes were compared to
two other groups of students. The first was taught using contemporary teaching methods while the second was taught conventionally. Research data was collected using observations, questionnaires and evaluation sheets. Results analysis revealed that this alternative way of teaching using a serious game was met with enthusiasm and caused positive reactions to students. They were engaged with the game effortlessly and the collaboration worked almost flawlessly. Compared to the other two forms of teaching, the learning outcomes were better in most cases. Further studies are recommended and implications are also discussed.