A number ending in an even number of zeros is always a perfect square.

Square of an odd number is always an odd number.

$1, 3, 6, 10, 15$, ...... are called triangular numbers.

There are $2n$ non-square numbers between the squares of consecutive numbers $n$ and $\left(n+1\right)$.

$\left(4, 6, 8\right)$ is a Pythagorean triplet.

How many natural numbers lie between ${25}^2$ and ${26}^2$?