Formal operations refers to the fourth stage in Piaget's Cognitive-developmental theory that is characterized by the capacity for flexible, reversible operations concerning abstract ideas and concepts, such as symbols, statements, and theories. Moreover, in Piaget's theory, it is the fourth and the final stage of Cognitive development , in which children over the age of 11 or 12 and beyond, when the individual begins to think more rationally and systematically about abstract concepts and hypothetical events and are able to apply abstract logical rules. It is characterized by the ability to think logically about abstract ideas and hypotheses as well as concrete facts; complex cognitive capacities, such as reasoning, hypothesis generation, and hypothesis testing .
List of books: Formal,operations