Developmental dyscalculia (DD) is a specific developmental learning disorder that is mostly synonymous with the terms math learning disorder, mathematics disorder, math learning disability, dyscalculia, and arithmetic disorder. The breadth and cumulative nature of skills and knowledge that comprise mathematics result in significant heterogeneity of math competence over the course of development. There are wide variations in individual math abilities and wide variation in the ways an individual can be good or bad at math. This heterogeneity makes the diagnosis and study of DD a difficult task.

DD may manifest as poor performance in many mathematical domains (e.g., algebra, geometry) or in one set of individual skills (e.g., counting, addition, subtraction). However, most researchers agree that DD can be defined as a neurodevelopmental disorder with a ...