The so-called root sign, the actual official name should be the root, which is the inverse operation of power.
The product of the multiplication of several identical numbers is called the power. For example: 2×2=2 flat (quadratic).
Conversely √4=2.
Power can be multiplied by n power, and roots can also be opened to n power. According to the agreement, you don't have to write 2 when you open the square, and the rest should indicate how many times you have opened it.