Skilled instructors observe consistent errors that young children may make in particular situations and seek ways to help children reform their thinking through conceptual understanding. Such teacher observations as those presented at the beginning of this article, combined with similar observations by teachers in other preschool and kindergarten classrooms, led to research of a more formal nature on early addition with numerals. The responses of the children documented in the research, in turn, inform teachers about strategies to use when introducing numerals into addition situations. A bibliography is provided.