Is zakat obligatory on residential properties if their value is exorbitant, and how is this zakat estimated?

There is no Zakat on houses owned for dwelling, no matter how high their value; this is based on the words of the Prophet, peace and blessings be upon him: "There is no sadaqah (Zakat) on a Muslim's slave or his horse." This Hadith is a foundational principle indicating that wealth acquired for personal use (that which is held for benefit) is not subject to Zakat, as it is occupied by essential needs and is not intended for growth.