<P> In mathematics, a negative number is a real number that is less than zero . Negative numbers represent opposites . If positive represents a movement to the right, negative represents a movement to the left . If positive represents above sea level, then negative represents below sea level . If positive represents a deposit, negative represents a withdrawal . They are often used to represent the magnitude of a loss or deficiency . A debt that is owed may be thought of as a negative asset, a decrease in some quantity may be thought of as a negative increase . If a quantity may have either of two opposite senses, then one may choose to distinguish between those senses--perhaps arbitrarily--as positive and negative . In the medical context of fighting a tumor, an expansion could be thought of as a negative shrinkage . Negative numbers are used to describe values on a scale that goes below zero, such as the Celsius and Fahrenheit scales for temperature . The laws of arithmetic for negative numbers ensure that the common sense idea of an opposite is reflected in arithmetic . For example, − (− 3) = 3 because the opposite of an opposite is the original thing . </P> <P> Negative numbers are usually written with a minus sign in front . For example, − 3 represents a negative quantity with a magnitude of three, and is pronounced "minus three" or "negative three". To help tell the difference between a subtraction operation and a negative number, occasionally the negative sign is placed slightly higher than the minus sign (as a superscript). Conversely, a number that is greater than zero is called positive; zero is usually thought of as neither positive nor negative . The positivity of a number may be emphasized by placing a plus sign before it, e.g. + 3 . In general, the negativity or positivity of a number is referred to as its sign . </P>

Where are negative numbers used in real life today