This study critically examined the math content knowledge (MCK) of teacher candidates (TCs) enrolled in a two-year Master of Teaching (MT) degree. Teachers require a solid math knowledge base in order to support students’ achievement. Provincial and international math assessments have been of major concern in Ontario, Canada, due to declining scores. Research aimed to investigate the development of TCs’ math capacities for effective teaching is important to teachers, school districts, universities, professional learning associations, and policy makers. The researchers of this study analyzed the basic numeracy skills of 151 TCs through pre- and post-tests. In addition, eight TCs took part in semi-structured interviews and shared their experiences in the MT math program. Test results indicated improvements in many areas, however, not all numeracy skills improved significantly. Interviews revealed TCs’ perceptions of the math test, courses, and instructors, as well as the importance of teaching math during their practicum placements. The researchers made recommendations to teacher education programs in areas such as: establishing minimum math competency standards, enhancing coherence between MT math courses and practicum placements, and providing additional support for TCs with low math proficiency.