The other 3 mathas were in

•  Dwarka -Gujarat
•  Puri – Odisha
• Sringeri- Karnataka

• Adi Shankara was one of the great Indian philosophers and social reformers  who was born in Kalady village on the bank of the River Periyar in Kerala in the eighth century.
• He was an advocate of Advaita or the doctrine of the oneness of the individual soul and the Supreme God which is the Ultimate Reality. 
• He met his guru, Swami Govindapada Acharya in a hermitage on the banks of the River Narmada. Under Govindapada Acharya’s guidance, he mastered Yoga, Vedanta and other systems and became a knower of the Brahman. Shankara travelled all over India and met the leaders of different schools of thought.
• He tried to revive Hinduism in India while Buddhism was gaining popularity.
• Adi Shankaracharya was known to reconcile various sects of  Vaishnavism, Shaivism, and Saktism with the introduction of the Pancayatana form of worship. It is the simultaneous worship of five deities of Ganesha, Surya, Vishnu, Shiva and Devi, arguing that all deities were different forms of the one Brahman. 
• Adi Shankara disappeared at the age of 32 in the year 820 C.E. In his short life, he majorly contributed towards shaping of Hindu culture and spirituality

Teachings

• Ādi Sankara is the first philosopher who identified the philosophical truths expounded in the Upaniṣads attached to the Vedas.
• He taught that Brahman, the only or Ultimate Reality, was formless and without any attributes. 
• Sankara considered the universe to be an illusion or maya and the Brahman or the Supreme Entity as Truth. 
• He preached renunciation of the world and adoption of the path of knowledge to understand the true nature of Brahman and attain salvation.