A number line is a tool used in mathematics to represent numbers on a continuous scale. It consists of an infinite line with points or marks at regular intervals, representing integers and real numbers. The line has zero as one end point and can be divided into any desired units, such as tenths or hundredths.
On the number line, positive numbers are represented by moving to the right from zero, while negative numbers are represented by moving to the left of zero. Zero is usually located at the center of the line, with numbers increasing in either direction. The distance between two consecutive points on a number line represents their difference.
Number lines can be used for various mathematical operations such as addition, subtraction, multiplication and division, ordering integers or rational numbers, finding absolute value, determining whether an equation is true or false, and solving equations involving inequality. They are also useful in understanding the concept of order of magnitude and comparing numbers.