Final answer:
The concrete operational stage is Piaget's third stage of cognitive development, where children aged 7-11 can use logic for concrete events but cannot handle abstract and hypothetical reasoning.
Step-by-step explanation:
The stage in which children become able to use logic to solve problems but are still unable to apply logic to abstract and hypothetical situations, according to Jean Piaget, is known as the concrete operational stage. This stage occurs from about age 7 to 11 years old.
Children in the concrete operational stage can think logically about concrete events and they have a developed sense of conservation. They know, for instance, that the amount of water remains the same when poured from one container to another, despite the change in shape.
However, they lack the ability to systematically handle abstract and hypothetical ideas that are the hallmark of the following formal operational stage, which begins around age 11.