Page 1 RA TIONAL NUMBERS 173 173 173 173 173 9.1 INTRODUCTION You began your study of numbers by counting objects around you. The numbers used for this purpose were called counting numbers or natural numbers. They are 1, 2, 3, 4, ... By including 0 to natural numbers, we got the whole numbers, i.e., 0, 1, 2, 3, ... The negatives of natural numbers were then put together with whole numbers to make up integers. Integers are ..., â€“3, â€“2, â€“1, 0, 1, 2, 3, .... We, thus, extended the number system, from natural numbers to whole numbers and from whole numbers to integers. Y ou were also introduced to fractions. These are numbers of the form numerator denominator , where the numerator is either 0 or a positive integer and the denominator, a positive integer. Y ou compared two fractions, found their equivalent forms and studied all the four basic operations of addition, subtraction, multiplication and division on them. In this Chapter, we shall extend the number system further . W e shall introduce the concept of rational numbers alongwith their addition, subtraction, multiplication and division operations. 9.2 NEED FOR RATIONAL NUMBERS Earlier, we have seen how integers could be used to denote opposite situations involving numbers. For example, if the distance of 3 km to the right of a place was denoted by 3, then the distance of 5 km to the left of the same place could be denoted by â€“5. If a profit of ` 150 was represented by 150 then a loss of ` 100 could be written as â€“100. There are many situations similar to the above situations that involve fractional numbers. Y ou can represent a distance of 750m above sea level as 3 4 km. Can we represent 750m below sea level in km? Can we denote the distance of 3 4 km below sea level by 3 4 ? W e can see 3 4 is neither an integer, nor a fractional number. W e need to extend our number system to include such numbers. Chapter 9 Rational NumbersRead More

211 videos|109 docs|45 tests

### What are Rational Numbers?

- Video | 02:29 min
### Chapter Notes - Rational Numbers

- Doc | 3 pages
### Introduction: Rational Numbers between two Rational Numbers

- Video | 01:13 min
### Worksheet - Rational Numbers

- Doc | 1 pages
### Understanding: Equivalent Rational Numbers

- Video | 00:47 min
### Example: Plotting Rational Numbers on a Number Line

- Video | 03:47 min

- Test: Rational Numbers - 2
- Test | 20 ques | 20 min
- Introduction: Plotting Rational Numbers on a Number Line
- Video | 02:04 min