ABSTRACT
Children, adolescents and adults with dyscalculia generally lack a reliable, intuitive number sense. As a result they:
have a poor understanding of the order of magnitude of numbers and how numbers relate to one another;
experience difficulty with estimation and approximation;
cannot generalize learning from a taught problem to a new problem;
fail to notice errors and inconsistencies in their own work;
have difficulties in performing mental calculations accurately;
rely very heavily on concrete counting and mechanical calculation as a substitute for more abstract reasoning.
