This study involved 48 students ages 9 to 12. The 29 experimental group students, divided into small groups, performed learning exercises designed to improve skills in analyzing and processing expressions frequently included in addition and multiplication problems. The exercises helped significantly to improve problem-solving performance. (MNS)

Three studies on the development of number concepts (counting, addition, subtraction, and place value) in seven- to nine-year-olds considered low attainers in mathematics were conducted. The search for a descriptive framework, the development of a diagnostic assessment instrument, and a longitudinal study are reported. (MNS)