### Theory:

In our earlier classes, we learned about power and exponent. Now, let us know about square and square numbers.

Look at the below pattern carefully.

In the above pattern:

The first picture has $$1$$ row and $$1$$ column.

The second picture has $$2$$ rows and $$2$$ columns.

The third picture has $$3$$ rows and $$3$$ columns.

The fourth picture has $$4$$ rows and $$4$$ columns.

$$1 \times 1 = 1^2 = 1$$

$$2 \times 2 = 2^2 = 4$$

$$3 \times 3 = 3^2 = 9$$

$$4 \times 4 = 4^2 = 16$$

Here, we multiply the number by itself, and we obtained a square of that number.

The numbers $$1$$, $$4$$, $$9$$ and $$16$$ are called square numbers.
If a natural number $$(m)$$ is expressed as a power of $$2$$, then the number $$(m)$$ is called a square number. That is $$m = n^2$$. A square number is also called a perfect number.

Important!
When we multiply a number by itself, we obtained a square of that number.