if there were 500,000 enslaved people in virginia in 1798, how many counted towards its population?

Under the U.S. Constitution’s original “three‑fifths compromise,” enslaved people were counted as three‑fifths of a person for purposes of representation and direct taxation, not fully excluded and not fully counted.

So, if Virginia had 500,000 enslaved people in 1798:

500,000×35=300,000500{,}000\times \frac{3}{5}=300{,}000500,000×53​=300,000

That means 300,000 enslaved people would have counted toward Virginia’s official population for representation in Congress and in the Electoral College.