Computer-based Number Categorization as an Intervention for Computer-based Number Line Estimation

The number line is a versatile tool. When used in estimation, it can serve as a visual representation of number. This study evaluated the relationship between sorting numbers by magnitude and number line estimation performance. Fifty-eight participants in Grades 1, 2, and 3 estimated values on a 0-100 number line over four sessions. During two intervention sessions they sorted numbers into 5 categories either linearly or nonlinearly before they estimated the same target values. The linear group’s number line estimates had less error than the nonlinear group’s estimates at posttest. In particular, the participants who started with low numeracy scores in the linear group outperformed their counterparts in the nonlinear group on the number line estimation task. Computer-based number categorization supports computer-based number line estimation skills when numbers are categorized linearly. This finding extends the representational mapping hypothesis to computer-based scaffolds.