Performance across different areas of mathematical cognition in children with learning difficulties

The performance of 210 2nd graders in different areas of mathematical cogni tion was examined. Children were divided into 4 achievement groups: childre n with difficulties in mathematics but not in reading (MD-only), children w ith difficulties in both mathematics and reading (MD/RD), children with dif ficulties in reading but not in mathematics, and children with normal achie vement. Although both MD groups performed worse than normally achieving gro ups in most areas of mathematical cognition, the MD-only group showed an ad vantage over the MD/RD group in exact calculation of arithmetic combination s and in problem solving. The 2 groups did not differ in approximate arithm etic and understanding of place value and written computation. Children wit h MD-only seem to be superior to children with MD/RD in areas that may be m ediated by language but not in ones that rely on numerical magnitudes, visu ospatial processing, and automaticity.