Absolute difference is a measure of the difference between two numbers or quantities, regardless of their signs. It is represented by the absolute value of the difference between the two numbers.

For example, if we have two numbers 5 and 10, the absolute difference between them is 5 (|10-5|=5). Similarly, if we have two numbers -10 and -5, the absolute difference between them is 5 (|-10-(-5)|=5). In both cases, the absolute difference is the same, even though the signs of the numbers are different.

Absolute difference is often used in mathematical and statistical calculations to compare two numbers or quantities. For instance, in statistics, absolute difference is used to measure the degree of dispersion or deviation of a set of data from its mean. It is also used in regression analysis to measure the difference between the predicted values and the actual values of a dependent variable.

In addition, absolute difference is used in geometry to measure the distance between two points. For example, if we have two points (1, 2) and (3, 4) on a coordinate plane, the absolute difference between their x-coordinates is 2 (|3-1|=2) and the absolute difference between their y-coordinates is 2 (|4-2|=2).

Absolute difference is also used in finance and economics to measure the difference between the actual value of a financial instrument and its predicted value. For example, if a stock is predicted to be worth $10 and its actual value is $8, the absolute difference between the two is $2 (|10-8|=$2).

Overall, absolute difference is a useful tool in a variety of mathematical and statistical applications, as it allows us to compare two numbers or quantities regardless of their signs. It provides a consistent measure of the degree of difference between two numbers, which can be useful in many different contexts.