The ability to classify objects is based on the idea of a relation. Some common characteristics among the objects must be known to the child for them to be grouped together. Classification work, that of determining a relation that allows objects to be grouped as belonging or not belonging to the class, is the basis for later work with definitions. Classification proceeds through at least three levels for the young child. First, simple classification is performed according to whether objects belong together; second, objects are classified as to disjoint sets; and last, multiple classification takes place in which objects may belong to two or more of the classes. This activity includes 4 sets with each set containing 10 cards. The materials come pre-cut with all corners rounded.
