Square Root : If $ x^2 = y \ $, we say that the square root of $y$ is $x$ and we write $y = x$.

Example 1. $ \sqrt{9}$ = $\sqrt{3 \times 3}$ = $3$

Example 2. $ \sqrt{16}$ = $\sqrt{4\times 4}$ = $4$

Note:

1. Square of a numbers is always end with 0, 1, 4, 5, 6, 9 in its unit place.
2. Square of a numbers can never have 2, 3, 7 and 8 in its unit place.

Cube Root : The cube root of a given number $x$ is the number whose cube is $x$. The cube root of $x$ is denoted by $ \sqrt[3]{x}$.

Example 1. $ \sqrt[3]{27}$ = $\sqrt[3]{3 \times 3 \times 3}$ = $3$

Example 2. $ \sqrt[3]{64}$ = $\sqrt[3]{4 \times 4 \times 4}$ = $4$