Some contemporary theories of numerical cognition posit that a generalized magnitude system may serve as a core primitive foundation for building number concepts. To date, however, these theories have largely privileged whole numbers and whole number analogs, relegating rational numbers to the background. In this talk, I will argue that more explicit attention to nonsymbolic ratio perception can account for the deep connections between whole numbers and other classes of number, while accounting for how continuous magnitudes can be mapped to specific numbers. By carving out a pivotal role for nonsymbolic ratio perception, this correction might help provide the basis for a more unified theory of numerical cognition.