On June 21, 1788, the Constitution became the official framework of the government of the United States of America when New Hampshire became the ninth of 13 states to ratify it. The journey to ratification, however, was a long and arduous process.

Often misinterpreted to mean that African Americans as individuals are considered three-fifths of a person or that they are three-fifths of a citizen of the U.S., the three-fifths clause (Article I, Section 2, of the U.S. Constitution of 1787) in fact declared that for purposes of representation in Congress, enslaved …

https://en.wikipedia.org/wiki/Three-fifths_Compromise

The Three-fifths Compromise was a compromise reached among state delegates during the 1787 United States Constitutional Convention. Delegates disputed whether and how slaves would be counted when determining a state's total population, as this number would determine a state's number of seats in the House of Representatives and how much it would pay in taxes. The compromise counted three out of every five slaves as people, giving the Southern states a third more seats in Congress and a third more electoral votes than if slaves had been ignored, but fewer than if slaves and free people had been counted equally. The compromise was proposed by delegate James Wilson and seconded by Charles Pinckney.[1]:143

In the US Constitution, the Three-fifths Compromise is part of Article 1, Section 2, Clause 3. Section 2 of the Fourteenth Amendment (1868) later superseded this clause and explicitly repealed the compromise.