The formal operational stage is the fourth stage in page’s theory cognitive development. Age from 12 to adulthood. Adolescents enter this age, they can gain the ability to think abstractly and manage to manipulate ideas in their heads, without reliance on concrete manipulation. Both genders can do maths calculations, and image the result of the specific actions, for example if Mariam is taller than Amira and Amira is taller than Mariam and who is tallest, this is an example of inferential reasoning, the ability to think about things that a child has not yet experienced and to bring that conclusion from it’s thinking. A child who draws a picture or uses objects are still in the concrete operational stage, and children who can figure out the reason of the answer in their heads are using formal operational thinking.