Effect of a number line intervention using DéCaLigne software on number accuracy and arithmetic in two children with mathematics learning disabilities.

Abstract

Individuals with Mathematics Learning Disabilities (MLD) often have difficulties in accurately estimating the position of numbers on a number line; such deficits may thus explain why they find arithmetic so challenging. The aim of the study was to investigate the effectiveness of an intensive and individualized number line intervention on number accuracy and arithmetic skill in children with MLD. A simple phase change across subjects and outcomes design was used. Two children (9 and 15 years old) practiced estimation and calculation, with corrective feedback, on the digital number line software DéCaLigne during three 30 minutes sessions per week for four weeks. Performance was assessed four times: one month prior to and immediately before the intervention, after the intervention to measure immediate learning, and one month later to measure maintenance. The children were assessed on their number accuracy (i.e., placing numbers on a number line), and performance on addition and subtraction computations with the number line (i.e., learning) and without (i.e., mental computation as transfer). Both children significantly improved their number accuracy and their arithmetic performance, both with and without the number line, between the second baseline and the immediate learning assessment after the intervention. They also maintained their number accuracy and their

arithmetic performance one month later. The results support the causal effect of practicing estimation and calculation with a number line on arithmetic skill. The effectiveness of the number line intervention offers hope to clinicians and teachers, but replications are essential to characterize it as an evidence-based practice.