Absolute value - Wikipedia
https://en.wikipedia.org/wiki/Absolute_valueThe definition of absolute value given for real numbers above can be extended to any ordered ring. That is, if a is an element of an ordered ring R, then the absolute value of a, denoted by |a|, is defined to be: where −a is the additive inverse of a, 0 is the additive identity, and < and ≥ have the usual meaning with respect to the ordering in the ring.
Absolute Value - mathsisfun.com
https://www.mathsisfun.com/numbers/absolute-valueNo Negatives! So in practice "absolute value" means to remove any negative sign in front of a number, and to think of all numbers as positive (or zero). Absolute Value Symbol To show that we want the absolute value of something, we put "|" marks either side (they are called "bars" and are found on the right side of a keyboard), like these examples: