The absolute value of an integer is the numerical value without regard to whether
the sign is negative or positive. On a number line it is the distance between the
number and zero.

The absolute value of -15 is 15. The absolute value of +15 is 15

The symbol for absolute value is to enclose the number between vertical bars such
as |-20| = 20 and read "The absolute value of -20 equals 20".