Which sentence states a fact?
Most Australians live in cities on the southeast coast, such as Sydney and Melbourne. The cities on the southeast and southwest coasts of Australia are too crowded.
A fact is something that can be proved true by research or observation.
George Washington became president of the United States in 1789.
This statement is a fact. It can be proved by researching what year George Washington was inaugurated president.
An opinion is something that a person believes, thinks, or feels. An opinion can be supported by evidence, but it cannot be proved true.
George Washington was a better president than Thomas Jefferson.
This statement is an opinion. People can have different ideas about what makes someone a "better" president, so the statement cannot be proved.
The first sentence states a fact.
Most Australians live in cities on the southeast coast, such as Sydney and Melbourne.
It can be proved by checking a population density map, or a map showing the populations in different areas, of Australia.
The second sentence states an opinion.
The cities on the southeast and southwest coasts of Australia are too crowded.
Too crowded shows what a person believes, thinks, or feels. Another person might have a different opinion about how crowded is too crowded.