Fifty 1-to 3-year-olds were asked to imitate: (1) the rolling of a cylinder down an incline and (2) the making of an incline with a board and a block. Their incorrect imitations and progress were videotaped and analyzed, and interpreted in light of Piaget's theory about the elaboration of logico-mathematical relationships in an interrelated way. The educational implication drawn is that the development of logico-mathematical knowledge as a network of interrelated mental relationships is a better goal for preschool mathematics education than isolated objectives, such as ability to sort, recognize shapes, and understand words like "first" and "second."Piaget (1936/1963, 1937/1954) observed babies' development of logico-mathematical knowledge during the first two years of life and later studied children's cognitive development after the age of four What happens between ages 2 and 4 is not well understood, and the purpose of this study is to fill part of this gap