Introduction to rational no

helpful for stuent ppt on rationa number cass 8

1. RATIONAL NUMBER By- Nandini Rai Class-8 th A Roll No.-27

2. INDEX Introduction Properties Rational Numbers on the Number Line

3. INTRODUCTION Rational Number are closed under the operations of Addition ,Subtraction , Multiplication. x+2=17 x=17-2 x=15 because this value of x satisfies the given equation. The solution 15 is a NATURAL NUMBER.

4. x+5=5 x=5-5 x=0 the solution gives the WHOLE NUNBER 0 (zero). x+18=5 x=5-18 x=-13 which is not a whole number. This led us to think of INTEGERS,(positive and negative) 2x=3 x=3/2 5x+7= 0 x= -7/5

5. PROPERTIES Commutivity Whole numbers Integers 3) Rational number a) Addition is commutative for Rational Numbers. b) Subtraction is not commutative for Rational Numbers.

6. - 3/2 and -7/5 this leads us to the collection of RATIONAL NUMBER. A number which can be wrttten in the form p/q where p and q are integers and q=0 cancel is called RATIONAL NUMBER. For example; -2/3, 6/7 are all rational number.

7. c) Multiplication is commutative for RATIO- -NAL NUMBERS. d) Division is not commutative for RATIONAL NUMBER. Associativity 1) Whole Numbers 2) Integers 3) Rational Number a)Addition is Associative for Rational Number.

8. c b) Subtraction is not Associative for Rational Numbers. c) Multiplication is Associative for Rational Numbers. d) Division is not Associative for Rational Numbers. Distributivity - Distributivity of Multiplication over Addition and Subtraction. - For all rational numbers a,b and c. - a( b+c ) = ab+ac a(b-c) = ab -ac

9. Reciprocal -We say that 21/8 is the Reciprocal of 8/21 and 7/-5 is the reciprocal of -5/7. 0(zero) has no Reciprocal. -We say that a Rational Number c/d is called the Reciprocal or Multiplicative inverse of another rational number a/b if a/b x c/d = 1

10. RATIONAL NUMBERS ON THE NUMBER LINE Natural Numbers 1 2 3 4 5 6 7 Whole Numbers 0 1 2 3 4 5

11. Integers -3 -2 -1 0 1 2 3 Rational Numbers -1 -1/2 0 ½ 1

12. THANKYOU The End