on the number axis, the distance from the point representing a number to the origin is called the absolute value of the number, and the absolute value is represented by "||". on the number axis, assuming a>b, and a>0, b>0, then the value representing the distance between the point of number a and the point of number b is read as the absolute value of ab, recorded as |ab|.

for example: |5| refers to the distance between the point representing the number 5 and the origin on the number axis. this distance is 5, so the absolute value of 5 is 5. similarly, |-5| refers to the distance between the point representing the number -5 and the origin on the number axis. this distance is 5, so the absolute value of -5 is also 5.

the absolute value of a non-negative number (positive number and 0) is itself, and the absolute value of a non-positive number (negative number and 0) is its opposite.

the absolute value of a is represented by "|a|". read as "the absolute value of a".

the absolute value of a real number a is always non-negative, that is, |a|≥0.

the absolute values ​​of two numbers that are opposites of each other are equal, that is, |-a|=|a| (because they are equidistant from the origin on the number axis).

if a is a positive number, x that satisfies |x|=a has two values ​​±a, such as |x|=3, then x=±3.