Arithmetic/Types of Numbers/Imaginary Number

Imaginary Number
An imaginary number is a number whose square is less than zero.

e.g.
 * $$i = \sqrt{-1}$$

Conjugate Number

 * $$-i = -\sqrt{-1}$$

Rules
1) i + i = 2i

2) i - i = 0

3) i x i = i²

4) i / i = 1

5) i + (-i) = 0

6) i - (-i) = 2i

7) i x (-i) = -i2 = 1

8) i / (-i) = -1