Abstract: This study compared 4th grade children in the U.S. and Taiwan on understanding (linearity, area, and volume. Taiwanese and American children were both under 50% correct for the concepts of area and volume in October. By May, Taiwanese children learned 90% of the targeted concepts. American children were still under 50% correct. During the following year, U.S. children received five weeks of instruction on linear, square, and cubic measure, or they received no instruction. Results showed significant increases on accurate knowledge of all measurement concepts, average score = 89%. Improvement was related, at the .72 level, to memory for forward going digit span. The control group did not improve on any type of measurement concept, despite their similar scores on memory for digit span. A third study showed that repeated practice on multiplication lowered the effects that digit span memory has on learning measurement concepts.