Lack of procedural knowledge was evident in findings that children of these ages frequently erred while using paper and pencil to solve multidigit addition and subtraction problems (Brown & Burton, 1978; Fuson & Briars, 1990; Kouba et al., 1989; Labinowicz, 1985; Stevenson and Stigler, 1992). Taken together, these results suggest that conceptual and procedural knowledge are related; Asian children have both, and American children lack both.