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presentation_natural_number_1594297879_388575.pptx
- 1. NUMBER SYSTEM (PART-2) We aregoing to study NATURAL NUMBERS in detail in this presentation(ppt). Types of Natural Numbers – UNIQUE NUMBER PRIME NUMBER COMPOSITE NUMBER
- 2. NATURAL NUMBER • Countingnumbers starting from 1 are Natural numbers. • Ex : 1,2,3,4,5,6,7,8,9,10…………………………………………… • 3 types of Natural numbers – Unique Number, Prime Number, Composite Number UNIQUE NUMBER : - - 1 is Unique Number. - 1 is neither prime nor composite. - 1 has only one factor, i.e, the number 1 itself.
- 3. PRIME NUMBER :- •Has only 2 factors: 1 and itself. • Ex:- 2,3,5,7,11,13,17,19,23,29…………………………………. • Factors of 2 - 1 and 2 (only 2 factors) • Factors of 3 - 1 and 3 (only 2 factors) • Factors of 5 - 1 and 5 (only 2 factors) • Factors of 11 - 1 and 11 (only 2 factors) • Factors of 47 - 1 and 47 (only 2 factors) NOTE – 2 is the only even prime number. (Important)
- 4. COMPOSITE NUMBER : •Has more than 2 factors • Ex:- 4,6,8,9,10,12,14,15,16,18,20,22 ……………………….. • Factors of 4 : 1,2,4 (3 factors) • Factors of 6 : 1,2,3,6 (4 factors) • Factors of 8 : 1,2,4,8 (4 factors) • Factors of 9 : 1,3,9 (3 factors) All the above numbers are having more than 2 factors, hence they are composite numbers.
- 5. Question:- How manyPrime numbers are below 50. Answer :- There are 15 Prime numbers below 50. Following are the prime numbers below 50- 2,3,5,7,11,13,17,19,23,29,31,37,41,43,47 The above numbers are having only 2 factors : 1 and itself, Hence they are prime numbers.
- 6. Question:- How manycomposite numbers are below 50. Answer : There are 33 composite numbers below 50. - 1 is unique number. - In the previous example we have seen that there are 15 prime numbers below 50. - Total number of natural numbers below 50 = 49 - Hence total number of composite numbers below 50 = 49-(1+15) = 33
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