What is the singleton (unit) set?

A singleton set is like a special box that can only hold one thing. It’s a set that has only one element inside.

Real-life example

Suppose we have a box that can only fit one toy. If we put a toy car in the box, that box is like a singleton set because it only has one thing inside—the toy car.

So, a singleton set is like a tiny box that can hold just one special thing!

Examples of singleton set

Singleton set of prime numbers

Consider a set, $S$, containing only the prime number $2$. This set can be expressed as:

Here, the curly braces indicate a set, and the set $S$ is a singleton set because it consists of only one element, which is the prime number $2$.

Singleton set in geometry

Consider a set, $T$, representing a singleton set of geometric shapes, specifically a single square. This set can be expressed as:

In this example, the set $T$ is a singleton set because it contains only one element, which is the geometric shape $square$.

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