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Opposite number or additive inverse of any number n is a number which, if added to n, results in 0, the identity element of addition. The opposite number for n is written as −n. For example, −7 is opposite to 7, because [math]-\!7 + 7 = 0[/math]. You can say that the opposite number of a number, is the negative version of the positive number.
Use absolute value witch means the distance between a number and 0