The Concrete operational stage
The Concrete operational stage is the hands-on stage. At this stage the recognition of the logical ability of the physical world, the realization that elements can be changed or transformed and still conserve may of their original characteristics, and the understanding that these changes can be reserved is acknowledged. The ability to solve concreted operational stage tasks involves an understanding of three basic aspects of reasoning: identify compensation, and reversibility. Another important operation mastered at this stage is the classification which depends on the ability to focus on a single characteristic in a set and group the objects according to the characteristics.