## Precalculus: Mathematics for Calculus, 7th Edition

The easiest way to find distance between two points on a straight line is to subtract the smaller value from the larger one. In this example, you would subtract $(-2.5)$ from $1.5$. This would translate to $1.5-(-2.5)$. When subtracting a negative, you add, so this would become $1.5+2.5$ which equals $4$.