Family of numbers

Family of numbers-

Complex number-It is denoted by "Z".

  Ex-0,-2,8,15/7,2i+8,√7.

Real number-It is denoted by "R".

 Ex-0,-5,27,3/8,√12.

Imaginary number-It is denoted by "I".

 Ex-2i,3+4i,-7i.

Note- i=√-1.

Properties of perfect square

Properties:-

1. Units digit of a perfect square can be-0(even number of zeroes),1,4,5,6,9.
Ex-100,81,144,225,676,289.
2. Digital sum of any perfect square can be-1,4,9,7.
Ex-289 digital sum=2+8+9=19,digital sum=10,digital sum=1.(until one digit). 
Note-perfect square cannot end with an odd number of zeroes and the digits2,3,7,8.