MHB Set Problems: Is My Statement about Circles True?

[jaychay]

Is the statement that I have circle is true ?
Because I feel like the solution in my textbook is wrong, I only learn that empty set is a subset of every set but it is not an element of a set.

 

[Evgeny.Makarov]

You are right: $\emptyset$ is not an element of $\{1, 2, 3\}$. The only elements of that set are 1, 2 and 3.

 

[HallsofIvy]

Of course, the empty set, $\phi$, is a subset of every set so it is true that $\phi\subset \{1, 2, 3\}$.