Absolute value

Imagine you're tracking how far your friend's house is from school. It doesn't matter which direction , north or south, left or right , you only care about the gap. That's exactly what absolute value does with numbers.

Absolute value (also called the modulus or numerical value) strips away the sign of a number and keeps only its size. Formally, $|x|$ is the distance of $x$ from zero on the number line. Distance is never negative , you can be zero steps away, but you can't be minus five steps away , so $|x|\ge 0$ for every real number $x$.

The surprising part: $|x|=0$ only when $x=0$ itself. Every other number, positive or negative, gives a strictly positive absolute value.