The 7 I learned about growing up are: Asia, Africa, North America, South America, Europe, Australia (or Oceania), and Antarctica.
Some combine Europe and Asia into Eurasia, bringing the number down to 6.
Others consider just 5: Eurasia, Australia (or Oceania), Africa, Antarctica, and the Americas.
The ones who only count 4 include: Eurafrasia, the Americas, Antarctica, and Oceania