generation educated under the 'pressure-free' system
Refers to Japanese students educated under the yutori (relaxed) education reforms from the late 1970s onward, often associated with reduced curriculum and Saturday school holidays. The term can carry a slightly critical or stereotyped nuance about the generation's perceived lack of academic rigor or common sense.
See also: ゆとり教育 (ゆとりきょういく)
It is said that the yutori generation has different values from the generation that received cram-style education.
Because he is from the yutori generation, people tend to think he calculated pi as 3.
Compound of ゆとり (yutori, 'leeway, relaxation') and 世代 (sedai, 'generation'), referring to the generation educated under the yutori education policy.