Question

what do these numbers mean:
|23|
-|23|
|-23|

Answer 1

The modulus of a number is the magnitude of that number. For example, the modulus of -1 ( |-1| ) is 1. The modulus of x, |x|, is x for values of x which are positive and -x for values of x which are negative.

Answer 2

the 2 vertical lines around the number means the 'absolute value of' that means you always take the positive value
so the third one = 23

the first one = 23
and 2nd = -23 because the negative sign is outside the vertical lines

Answer 3

absolute value or magnitude (as Abmon said)

Answer 4

or modulus