Fluency with basic facts has traditionally meant fast and accurate recall. Arthur J. Baroody argues that when instruction focuses on memorizing basic facts by rote, many–but not all–children can achieve efficient and accurate fact recall or "partial fluency." In a course taught by the developmental psychologist Herbert Ginsburg, Baroody learned that children are not simply passive learners but active thinkers and constructors of knowledge. It was fascinating to him that young children, without explicit instruction, could make sense of arithmetic situations and devise their own counting and reasoning strategies for determining sums and differences. Teachers were well aware of the importance of basic combination fluency in the early grades. Children who achieve true combination fluency have, by definition, a richer understanding of numbers and numerical relationships and are thus more likely to reason logically and be better problem solvers–be generally more successful at mathematics.