5. Number line.

 

5. Number line.

Learn and Remember :

• Number Line : When points on a line represent numbers, the line is called a number line. On a number line point O represents the number 0 (zero).
• Positive integers are represented by points to the right of zero and the negative integers are represented by points to the left of zero on a number line.
• Note that natural numbers, integers are rational numbers. Rational numbers can be represented on a number line.
• To represent a rational number  ⅔  on the number line, the distance between two consecutive integers is divided into three equal parts.

Between any two numbers on a number line, the number which is to the right is greater than the number to the left.

  • Distance and Coordinates : The distance between two points on a number line can be calculated from the coordinates of those two points. The distance between two points = the greater coordinate – the smaller coordinate

e.g. A↔ - 3, B ↔5. d (A, B) = ?

Here, 5 > -3    

∴ d (A, B) = 5-(-3)=5+3= 8.

• The number denoting the distance is always positive.

[The numbers corresponding the points on the number line are called the coordinates. The point corresponding to a number on the number line is called the graph of that point.)