In mathematics, a stands for letters and can be used instead of numbers.
If a and 1 are opposite, then a=- 1, |- 1|= 1.
Absolute value is the distance from a point corresponding to a number on the exponential axis to the origin, which is represented by "||". |b-a| or |a-b| represents the distance between the point representing a and the point representing b on the number axis.
Extended data:
Some properties of absolute value:
(1) The absolute value of a positive number is itself; The absolute value of a negative number is its reciprocal; The absolute value of 0 is still 0. The absolute value of a special zero is both itself and its reciprocal.
(2) The absolute value of any rational number is non-negative, that is, the absolute value of any rational number is greater than or equal to 0.
(3) Compared with two negative numbers, the absolute value is larger but smaller.
(4) The absolute values of a pair of opposites are equal.
References:
Baidu encyclopedia-absolute value