When I multiple two negative numbers together is my answer positive or negative?

My favourite way to remember whether my answer is positive or negative when I multiply two numbers is to think of the following:

a) If you multiply two numbers with the SAME sign (i.e. two positive numbers or two negative numbers) the result will be POSITIVE.

+  x  +  = +

-  x  -  =  +

b) If you multiple two numbers with OPPOSITE signs the result will be NEGATIVE. 

-  x  +  = +

+  x  -  =  + 

For example:

a)

6  x  2  = 12

-6  x -2  = 12

b)

-6  x  2  =  -12

6  x  -2  =  -12