This study examined parent-child math talk within three contexts (formal learning; guided play; unguided play) in order to identify characteristics of activities supporting high-quality math engagement. Seventy-two dyads of parents and 4- and 5-year-olds were observed using a set of toy foods; instructions and materials varied across conditions. Parents and children engaged in the most math talk in formal learning; guided play also yielded more math talk than unguided play. Parents rated the formal learning and guided play activities as equally supportive of math learning, but rated the guided play activity as more enjoyable than the formal learning activity. The findings have implications for how parents should be encouraged to support preschoolers' math learning.