How many eras has earth gone through which is longest and shortest?

Earth has gone through four major geological eras: the Precambrian, Paleozoic, Mesozoic, and Cenozoic. The longest era is the Precambrian, lasting nearly 4 billion years, while the shortest is the Mesozoic, which lasted about 180 million years. Each era is characterized by significant geological, climatic, and biological changes.