Explanation:

• Ordinarily, all business of the legislature requires that a motion or resolution or bill should get the support of a simple majority of the members voting at that time.

• Suppose that at the time of voting on a bill, 247 members were present in the house and all of them participated in the voting on the bill. Then, the bill would be passed if at least 124 members voted in favor of the bill.

• It is not so in the case of an amendment bill. Amendment to the Constitution requires two different kinds of special majorities:

•  in the first place, those voting in favor of the amendment bill should constitute at least half of the total strength of that House.
• Secondly, the supporters of the amendment bill must also constitute two-thirds of those who actually take part in voting.

• In the Lok Sabha total seats are 552. However, some of the seats are vacant and there are 545 members. Therefore, any constitutional amendment must be supported by a minimum of 273 members. Even if only 300 members are present at the time of voting, the amendment bill must get the support of 273 out of them.

• Both Houses of the Parliament must pass the amendment bill separately in this same manner (there is no provision for a joint session). For every amendment bill, this special majority is required.