Addition:
Let -a be a negative integer
Let b be a positive integer
If the signs are alike, the sum is always the sign.
Example:
-a + -a = -c
b + b = c
If the signs are different, and a = b, then the sum is 0.
Example:
a = b
-a + b = 0
b - a = 0
If -a > b then,
-a + b = -c
b - a = -c
If -a < b then,
-a + b = c
b - a = c
Subtraction
Those are just like addition. (NOTE: JUST LIKE)
Multiplication and Division
If the signs are alike, the answer is positive.
Means:
(-a)(-a) = c
(b)(b) = c
and
-a/-a = c
b/b = c
If the signs are unlike, the answer is negative.
Means:
(-a)(b) = -c
(b)(-a) = -c
and
-a/b = -c
b/-a = -c
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