Children's early mathematical abilities are fundamental to their later academic achievement. An interest in mathematics in the early years is likely to establish a positive attitude to later mathematical learning, hopefully sustaining continued interest in mathematics and mathematical learning. Approaches to early mathematics teaching in the early years, however, are typically adult-initiated, which may fail to capture children's interest. Given the importance of children's motivation and sustained interest, the study described here strove to spark children's interests in mathematical problems in everyday life. The study sought to determine if children would incorporate more numeracy-related concepts into their free play if exposed to adult demonstrations of age-appropriate numeracy activities such as patterning. For at least 15 min three times weekly, participating children's parents and educators demonstrated numeracy problem-solving nearby, while children engaged in other activities. Demonstrations were thought to ascribe social value to the problem-solving activities. If children became interested in participating, adults told them to wait until the demonstrations finished, further indicating social value. Results show these children chose to play with numeracy-related activities in their free play time at preschool significantly more than children in a control group. These results suggest that seeking to foster children's interest in mathematics through child-initiated play, rather than prescribing adult-initiated mathematics activities, may be an important means of laying the foundation for lifelong mathematics learning. Ascribing social value to numeracy applications is proposed as a new approach to teaching mathematics in the early years.