I don't know why we call it a national debt.

Except to say, this is how much interest we will owe this year.

The debt can never be paid off. There isn't enough money in the world to pay off all the loans. That's just fractional reserve lending.

So, why do we even pretend that it will get paid back?
Every person should know that the national debt equals dollars in circulation.
Get rid of one, get rid of the other.