Square is that multiplication of number by itself. square root is opposite of square.
symbole of square is √ it is called radical
ex. take square of 4 is 16 [4*4=16]
square root of 4 is 2 [√4 = 2]
you can do with differant mathod like with calculator, by hand without calculator and square root alorithm [ you can use matlab for this also]