Draw any line segment, say $\overline{AB}$. Take any point C lying in between.  Measure the lengths of AB, BC, and AC. Is $AB=AC+CB$?

Given :

Draw a line segment $\overline{AB}$ and mark the point C in between A and B.

To do :

We have to find, whether $AB=AC+CB$.
 

Solution :

In the above figure, 

AB is a line segment and Clies between A and B.

So, the points A, B, and C are collinear.

Therefore, $AB = AC+CB$.