Learning of arithmetic requires sufficient working memory capacity to hold the original problem in memory while computing the answer so that the problem and answer can be associated. However, children labeled as mathematically disabled cannot hold as much numerical information in memory as age peers (Geary, Bow-Thomas, & Yao, 1992; Koontz & Berch, 1996.) Limited conceptual understanding of arithmetic operations and counting adds further obstacles to these children's learning of arithmetic (Hitch & McAuley, 1991; Geary, 1994).