Introduction to practice number line

A number line is a line on which real numbers are placed according to their value. For example, the number 3.5 or 3 1/2 corresponds with the point on a number line that is halfway between the numbers 3 and 4. Each point on a number line corresponds to a real number, and each real number has a unique point on the Number line that corresponds only to that number. Number lines are valuable tools which are easily used to illustrate the mathematical concepts such as subtraction, addition and positive and negative numbers.          

The number line is usually represented as a horizontal line. An arrowhead on either end of the line is suggests that the line  continues indefinitely in the positive and negative real number's which are denoted by ‘R’. The real numbers may be irrational and rational numbers, integers, whole numbers or also natural numbers.      

Steps to Draw a Number Line:

In order to draw a number line,

Draw a straight line with 1 inch divisions.
Position the bottom edge of your ruler at the start of the line. Mark each 1inch measurement divisions on the line until you reach the end of the line. Draw an arrow head (i.e., "<" and ">") on the left and right ends of the line.
 Now, draw a perpendicular line at the centre and label it "0” where both the lines meet.
The divisions on the right hand side of the horizontal line will be the positive divisions i.e., numbers are prefixed with “+” sign and written as +1   +2   +3   +4   +5   +6……….

·       The divisions on the left hand side of the horizontal line will be the negative divisions i.e., numbers are prefixed with “-” sign and written as -1   -2   -3   -4    -5   -6………..

The points on a number line are called as the coordinates and the zero point is called the origin and the numbers on the right side of the origin are the positive numbers and those on the left side of the origin are the negative numbers. Hence the number line is divided as two symmetric halves by origin.

Examples for Practice Based on Number Line:

Below are the examples on how to perform addition and subtraction using Number line



 Ex 1: +6  - +2

  Sol: +6 - +2 = +6  - 2 = +4

  Ex 2: +8  +  +2

 Sol: +8  +  +2 = +10

 similarly,

+7 - +10 = +7 - 10 = -3
+7 + -10 = +7 - 10 = -3
+7+ +10 = +7 + 10 = +17
-7 - -10 = -7 + 10 = +3