Okay, so like most of my geography books from elementary school were wrong then.
They're not really wrong. The concept of "continents" is highly arbitrary and vague; there are a lot of variations on the number of continents depending on what model you're using. According to different conventions, any of the following regions can be considered continents:
-Africa
-Antarctica
-Asia
-Australia
-Europe
-North America
-South America
-Americas (North and South America as one continent)
-Eurasia (Asia and Europe as one continent)
-Euro-Afrasia (Asia, Europe and Africa as one continent!)
-Oceania (Australia and Pacific islands as one "continent")
-and some models don't count Antarctica (counting it only as an "island" I guess)