State the teachings of Adi Shankaracharya. Name the four monastic centres founded by him.

Teachings of Adi Shankaracharya:

1. He advocated the doctrine of the oneness of the individual soul and the Supreme God, which is the Ultimate Reality. This doctrine is known as Advaita.
2. He taught that Brahman, the Ultimate Reality, was formless and without any attributes.
3. He preached renunciation of the world and urged everyone to adopt the path of knowledge to understand the true nature of Brahman and attain salvation.

The four monastic centres (mathas) founded by him are at Sringeri (Karnataka), Dwarka (Gujarat), Puri (Odisha) and Jyotirmath (Uttarakhand).