Rules for Adding Integers
LIKE SIGNS (+) + (+) or (-) + (-)
Find the sum of their absolute values and use the sign common to both integers.
UNLIKE SIGNS (+) + (-) or (-) + (+)
Find the difference of their absolute values and use the sign of the integer with the greater absolute value.
Rule in Subtracting Integer
To subtract an integer, add its opposite
For all numbers a and b,
a - b = a + (-b).