Research Findings: The current study analyzed the relation between the amount of mathematical input that preschool children hear (i.e., math talk) from their mothers in their homes and their early math ability a year later. Forty mother-child dyads recorded their naturalistic exchanges in their homes using an enhanced audio-recording device (the Language ENvironment Analysis System). Results from a sample of naturalistic interactions during mealtimes indicated that all mothers involved their children in a variety of math exchanges, although there were differences in the amount of math input that children received. Moreover, being exposed to more instances of math talk was positively related to children's early mathematical ability a year after the recordings, even after we controlled for maternal education, self-regulation, and recorded minutes. Practice or Policy: These findings improve the understanding of how mothers use math with their preschool children in naturalistic contexts, providing some insight for parents into how to foster children's math skills through verbal input in their normal routines. Moreover, these findings inform kindergarten teachers and practitioners about the math input that children receive at home, which may encourage them to adapt their practice by considering the home environment.