Points Q, R, S, and T are plotted on the number line.

A number line is shown ranging from negative two to two with every one-half increment labeled. Between each one-half increment is a tick mark. Point Q is on the tick mark between negative one and one-half and negative one. Point R is on the tick mark between negative one-half and zero. Point S is on the tick mark between zero and one-half. Point T is on the tick mark between one-half and one. [3]

Which two plotted points have a sum of zero?
Explain how the number line can be used to show that the sum of the two points you identified is zero.
Explain how the number line can be used to determine the sum of the location of point T and -112.