Question

Define singleton set with an example. Is a set of even prime numbers a singleton?

Answer 1

Singleton set is a set that has only one element.

Examples of singleton set are $\left\{9\right\}$, $\{x:x$ is a positive integer that has only one factor$\}$

Since there is only one even prime number i.e.$2$, and the rest of the prime numbers are odd numbers.

Thus, a set of even prime number $\left\{2\right\}$ is a singleton set.