The importance of mathematics at an early age stems from the finding that early competence is likely to lead to future mathematics achievement (Duncan, Dowsett, Claessens, Magnuson, Huston, Klebanov, Pagani, Feinstein, Engel, Brooks-Gunn, Sexton, Duckworth, & Japel, 2007). Moreover, individuals that do well in mathematics are likely to have increased overall income earnings (Paglin & Rufolo, 1990; Rivera-Batiz, 1992), while individuals that do not perform as well in mathematics are essentially limiting their potential for career options and labor market earnings (e.g., Paglin & Rufolo, 1990). Studies attempting to better understand the processes related to mathematic underachievement have proposed different ability groups to explain deficits in mathematics. The purpose of this study is to determine whether discrete latent classes can be observed in children within the continuum of mathematic achievement ability. The findings provided partial evidence for the hypothesized ability subgroups along the math achievement ability distribution. The ability groups observed were further tested for external validity. Evidence for the external validity of measures suggests that the domain specific indicators played a critical role in distinguishing between ability groups. The findings gathered from this research support the notion of mathematics learning ability subgroups and further improves the identification of children at risk for math difficulties.