In Piaget's stages of cognitive development, the concrete operational child begins to think logically. Operations are associated with personal experience. Operations are in concrete situation, but not in abstract manipulation.Concrete operations allow children to classify several classes into a bigger group or to combine a number of classes in any order. Although objects are moved or reordered, no change takes place.In addition, concrete operations allow children to order objects in terms of more than one dimension. Children at the concrete operational stage can solve conservation tasks. The operational thought is reversible. The concrete operational child can operate an action, and then go back to the original condition. For instance, 3 + 2 = 5 and 5 – 2 = 3.The limitation of the third stage of cognitive development is that operations are only carried out on concrete objects, and limited to two characteristics at the same time.