“…Moreover, in studies focusing on children with mathematical learning disabilities, school children showed deficits in these quantity-number competencies (Gaupp, Zoelch, & Schumann-Hengsteler, 2004;Geary, Hamson, & Hoard, 2000;Geary, Hoard, Byrd-Craven, & DeSoto, 2004;Landerl, Bevan, & Butterworth, 2004). Confirming the special importance of the quantity to number-word linkage, for instance, the 7-year-olds with Williams Syndrome in the study by Ansari, Donlan, Thomas, Ewing, Peen, and Karmiloff-Smith (2003) demonstrated an extremely delay in the understanding of the cardinality principle (Level II), despite the fact that they could recite the number-word sequence (Level I) in the assessed number range almost without errors.…”