ㄧ-4ㄧ=ㄧ+4ㄧ=4

-ㄧ-4ㄧ=-4

It means: it represents the actual distance from the point on the number axis to the origin (it will never be negative).

Three laws: the absolute value of a positive number is itself.

The absolute value of zero is zero, and the absolute value of negative number is its inverse (positive number).

For example: A < 0, then ㄧㄧ a =-a (-a) is a positive number.

In mathematics, absolute value or modulus |? x？ Nonnegative value of |

Regardless of its sign, that is |x | = x means positive x, | x | = -x means negative x (in this case -x is positive), | 0 | = 0. For example, the absolute value of 3 is 3, and the absolute value of -3 is also 3. The absolute value of a number can be considered as the distance from zero. ?

The generalization of absolute value of real number appears in various mathematical settings, such as complex number, quaternion, ordered ring, field and vector space to define absolute value. Absolute value is closely related to concepts such as size, distance and norm in various mathematical and physical environments.