what is the opposite of a number called
In mathematics, the additive inverse of a number a is the number that, when added to a, yields zero. This number is also known as the opposite (number), sign change, and negation. For a real number, it reverses its sign: the opposite to a positive number is negative, and the opposite to a negative number is positive. Zero is the additive inverse of itself. The additive inverse of a is denoted by unary minus : â a (see the discussion below). For example, the additive inverse of 7 is â7, because 7 + (â7) = 0, and the additive inverse of â0.3 is 0.3, because â0.3 + 0.3 = 0.