PROCEDURE FOR SUBTRACTING INTEGERS
a - b = a + (-b)
To subtract, add the opposite of the number to be subtracted.

USES FOR THE " - " SYMBOL
Minus is used to indicate subtraction, an operation symbol.
Negative is used to indicate those numbers to the left of the origin on a number line.
Opposite is used to signify an equivalent distance from the origin, but in an opposite direction. This is a number that can be either positive or negative. The symbol "-x" is read "the opposite of x" and should not be read "negative x" or "minus x."