A class of 14 kindergartners in Japan was videotaped while playing a card game in groups of three involving the placement of cards in numerical order. The children were followed up in first grade, and it was found that development in one area of logico-mathematical knowledge (for example, the making of temporal relationships) stimulates development in other areas (such as classification and numerical reasoning). This specific, interrelated mode of structuring was not expected and suggested that it is unwise for adults to try to plan a sequence of development. The implication of the findings is that it may be better to provide "natural" play activities that encourage children to think logico-mathematically than to conceptualize specific standards for 3-to-6-year-olds' mathematics education.