The absolute value of a number is the distance of that number from zero on a number line. So, the absolute value of -12 would be 12 since it is 12 units away from zero on the number line.
The absolute value of -12 is 12. It’s just like regular algebra, where the absoulte value of a number is just the number itself, without the negative sign. So for example, the absolute value of 5 is 5, and the absolute value of -5 is also 5.