DISTANCE FORMULA (ON NUMBER LINE)
The distance between two points is the absolute value of the difference between their coordinates.
If P has coordinate x1 and Q has coordinate x2, PQ=|x2-x1|or|x1-x2|
What is the length of EF?
The coordinate of E is 2 and the coordinate of F is 5. The length of EF is the distance between E and F on the numberline.
So, EF = |5 – 2| = |3| = 3.