In math, a number line can be defined as a straight line with numbers placed at equal intervals or segments along its length. A number line can be extended infinitely in any direction and is usually represented horizontally. In elementary mathematics, a number line is a picture of a graduated straight line that serves as an abstraction for real numbers, denoted by. Every point of a number line is assumed to correspond to a real number and every real number to a point. A number line can be used as a tool for comparing and ordering numbers and also performing operations such as addition and subtraction. Numbers on a number line include all sets of numbers, namely natural and whole numbers. An example of a set of whole numbers is: 0, 1, 2, 3,4,5,6 and so on.