3.The markings on the number line are evenly spaced. Label the other markings on the numberline.+-2.5-10

The difference between the -1 marking and -2.5 marking = -1 - (-2.5)
The difference between the -1 marking and -2.5 marking = -1 + 2.5
The difference between the -1 marking and -2.5 marking = 1.5
There are two markings between -2.5 and -1