Answer:

Positive and negative numbers such as +3 and –5 are called directed numbers because when represented on a number line the direction in which they are measured from the origin has to be taken into account.

Directed numbers are met in everyday life as temperatures. 0₂C is the origin: it is the freezing point of water. Negative numbers such as –8 are used to indicate temperatures below freezing, and positive numbers (usually with the + sign omitted) indicated temperatures above freezing.