What are the 2 rules that make a number not real

Question

What are rules that make a number not real

 

Answer 1

I am not sure what you mean by "2 rules that make a number not real."  If it has an imaginary part, it is not real.  For example,

 

z = 2 + 3i

 

is not real, because 

 

3i = 3√(-1),

 

and

 

i = √(-1)

 

is imaginary.