Last night as I lay in bed I figured something out.
Here is a basic number pattern that all addition follows:
(2+2=4)Even+Even=Even
(3+1=4)Odd+Odd=Even
(2+1=3)Even+Odd=Odd


Identical is the pattern of positive and negative:
- * - = +
- * + = -
+ * += +

Multiplication patterns go as so:
Even*Even=Even
Even*Odd=Even
Odd*Odd=Odd
This is IDENTICAL to the addition patterns.


Even/Even=Odd or Even
Odd/Odd=Odd
Even/Odd=Ratio 
Division is the one piece that doesn't seem to fit with the rest but...


What are the meaning and affects of these rules? I don't know, but they surely have some kind of significance. I know how to check my basic addition quickly. How can this be used? Has anyone ever noticed their importance? I don't know, but it sure is helpful to me.