Final answer:
Representatives and direct taxes must be apportioned among the states according to their population, as outlined in Article I, Section 2 of the U.S. Constitution. This ensures fair representation and tax distribution among the states, with a census every ten years for current population data.
Step-by-step explanation:
The two things that must be shared fairly among the states according to their "respective numbers" are representatives in the House of Representatives and direct taxes. This requirement is outlined in Article I, Section 2 of the United States Constitution. Representatives and direct taxes are apportioned based on the population of each state, ensuring a more equitable representation and tax distribution.
It is important to note that while every state has equal representation in the Senate with two senators, the representation in the House is determined by the state's population. Moreover, the power to levy and collect taxes is a concurrent power, allowing both federal and state governments to do so. The actual enumeration of people, directed by law, takes place every ten years to determine the appropriate apportionment of representatives.