Putting the "th" in tenths: The role of labeling decimals in revealing place value structure

Abstract

Language is a powerful cognitive tool. For example, labeling objects or features of problems can support categorization and relational thinking. However, little is known about their role in making inferences about the structure of mathematics problems. We test the impact of labeling decimals such as 0.25 using formal place value labels (“two tenths and five hundredths”) compared to informal labels (“point two five”) or no labels on children’s problem-solving performance. Third- and fourth-graders (N = 104) were randomly assigned to one of three conditions (formal labels, informal labels, or no labels) and learned to label decimals while playing a decimal magnitude comparison game and number line estimation task. Formal labels facilitated performance on comparison problems that required understanding the role of zero and place value structure. However, formal labels hindered performance on some problems that required explicit understanding of place value magnitudes. Findings provide some evidence for how the language teachers and students use impacts problem-solving success.