Question

To which subset of the real numbers does the numbers does the number (square root) 25 belong

Answer 1

The square root of a number $y$ is another number $x$ such that $x^2 = y$.

So, the square root of 25 is another number x such that $x^2 = x \cdot x = 25$

You can clearly see that the integer number 5 satisfies this request, so the square root of 25 belong to the integer numbers set, denoted as $\mathbb{Z}$