Answer:
 addition is subtraction of the opposite, and vice versa
Explanation:
Subtracting an integer is the same as adding its opposite. Likewise, adding an integer is the same as subtracting its opposite.
 4 - 3 = 4 + (-3) = 1
 4 + (-3) = 4 - 3 = 1
Or, ...
 4 - (-3) = 4 + 3 = 7
 4 + 3 = 4 - (-3) = 7