Nine mathematics tests were devised on lines suggested by the Piagetian model. One hundred and one girls, chosen from three schools (primary, junior secondary and senior secondary), were tested on items which varied on two dimensions, viz., the abstractness of the elements operated upon and the interrelationships of the operations in the item which defined its structure. As predicted, items with both concrete elements and structure were successfully handled by all age groups; as either structures or elements were made more abstract the younger age groups began to fail and only the oldest group had any success when both structures and elements were made more abstract. Implications were seen in the study which would be of interest to psychologists working with the Piagetian model as well as to teachers and curriculum planners.