Question

The points -4 and 5 are plotted on a number line. What is the distance, in units, between the two points?

Answer 1

The distance between two numbers is the absolute value of their difference.

Note that the order doesn't matter, since the distance between A and B is the same as the distance between B and A, obviously:

$d=|-4-5|=|-9|=9$

$d=|5-(-4)|=|5+4|=|9|=9$

So, the two points are 9 units away.