Definition of Square Roots: The square root of a number $x$ is a non-negative value that, when squared, equals $x$ (e.g., $\sqrt{9} = 3$ because $3^2 = 9$).

Square Root Symbol: The square root symbol $\sqrt{}$ always represents a non-negative result, so $\sqrt{16} = 4$, not $-4$, even though $(-4)^2 = 16$.

No Square Roots of Negative Numbers: The square root of a negative number is undefined in real numbers (e.g., $\sqrt{-1}$ is not possible in real numbers).

Examples of Perfect Squares: Knowing perfect squares like $144 = 12^2$ helps in quickly identifying square roots without calculation.