Find the distance between points on the coordinate line A (-0.21) B (-5.1).

In order to find the distance between two points, it is necessary to subtract the point that has a smaller coordinate from a point that has a large coordinate. That is, first we need to compare the coordinates of these points.
In our case, point A (- 0.21) and point B (- 5.1). Of the two negative numbers, the larger is the number whose modulus is less, that is, – 0.21 will be more than – 5.1.
Let’s find the distance between the points:
AB = – 0.21 – (- 5.1) = – 0.21 + 5.1 = 4.89.

Therefore, the distance between points A and B is 4.89 units.
Answer: the distance between points A and B is 4.89 units.