A number line is a horizontal straight line used to represent numbers visually. Numbers are placed along the line at equal intervals jointly with a vertical segment at each interval.

The arrows in the line indicate that the line extends infinitely on the left- and right-hand sides. A number on the left-hand side of the line is always less than a number on the right-hand side.

Natural Numbers on a Number Line

Natural numbers can be represented in a number line that starts from $1.$ Then $2,$ $3,$ $4,$ and so on, are marked at equal distances along the line to the right of $1.$

Whole Numbers on a Number Line

A number line can also be used to represent whole numbers. The line begins at $0$ and the rest of the whole numbers are drawn along the line to the right.

Keep in mind that all natural numbers are whole numbers, but not all whole numbers are natural numbers.

Integer Numbers on a Number Line

A number line can display integer numbers by extending it on the left- and right-hand side of zero. The positive integers or natural numbers will be on the right-hand side, and the negative integers will be on the left-hand side of zero.

Real Numbers on a Number Line

The number line is not limited to only showing natural, whole, and integer numbers. Real numbers can be also displayed on a number line. A real number can be represented by a unique point on the number line. The point associated with the real number is called a coordinate in a number line for real numbers. The number $0$ is called the origin. Positive real numbers are on the right-hand side of $0,$ and negative real numbers are on the left-hand side of $0.$