You know what
I'm old enough to be educated in an old soviet school. We there distinguished a so-called 'parts of the world' (as a cultural term) from 'continents' (as a geophysical term).
So there is 'America' as a 'part' but not 'continent' and also a 'New World' contained both Americas and Australia +New Zealand -- this is also a 'part of the World' -- a sociocultural term. The same for 'Europe', 'Middle Asia', 'Middle East'. And there were only 6 continents out there. Easy enough.
But I've asked my daughter and guess what? Now they're learn in a different manner, now they have all the 7 continents (with separate Europe and Asia). Things are more complicated than I thought before =)
Re^4: How many continents have you visited?