Why was the ratification of the 3/5ths Compromise so important to the new nation?

The north had more people than the south during this time, so the south saw it as unfair because the north would receive more representatives in the house of representatives than the south, resulting in more votes for the north. So the 3/5 compromise was made to count 3/5 of the slaves so the south could receive more representatives in the house of representatives.

hope this helps :)