NCERT Solutions for Class 6 Maths Chapter 3 PDF Download
The chapter covers factors, multiples, prime and composite numbers, divisibility tests, common factors, common multiples, prime factorization, highest common factor, lowest common multiple, and related problems. Specific problems related to these topics are divided into 7 exercises for easy identification.(a) 24
(b) 15
(c) 21
(d) 27
(e) 12
(f) 20
(g) 18
(h) 23
(i) 36
Solution: (a) 24 = 1 x 24 24 = 2 x 12 24 = 3 x 8 24 = 4 x 6 The factors of 24 are: 1, 2, 3, 4, 6, 8, 12, and 24. (b) 15 = 1 x 15 15 = 3 x 5 The factors of 15 are: 1, 3, 5, and 15. (c) 21 = 1 x 21 21 = 3 x 7 The factors of 21 are: 1, 3, 7, and 21. (d) 27 = 1 x 27 27 = 3 x 9 The factors of 27 are: 1, 3, 9, and 27. (e) 12 = 1 x 12 12 = 2 x 6 12 = 3 x 4 The factors of 12 are: 1, 2, 3, 4, 6, and 12. (f) 20 = 1 x 20 20 = 2 x 10 20 = 4 x 5 The factors of 20 are: 1, 2, 4, 5, 10, and 20. (g) 18 = 1 x 18 18 = 2 x 9 18 = 3 x 6 The factors of 18 are: 1, 2, 3, 6, 9, and 18. (h) 23 = 1 x 23 The factors of 23 are: 1 and 23. (i) 36 = 1 x 36 36 = 2 x 18 36 = 3 x 12 36 = 4 x 9 36 = 6 x 6 The factors of 36 are: 1, 2, 3, 4, 6, 9, 12, 18, and 36. 2. Write the first five multiples of:(a) 5
(b) 8
(c) 9
Solution: (a) First five multiples of 5 are: 5 x 1 = 5 5 x 2 = 10 5 x 3 = 15 5 x 4 = 20 5 x 5 = 25 Therefore, five multiples of 5 are: 5, 10, 15, 20, and 25. (b) First five multiples of 8 are: 8 x 1 = 8; 8 x 2 = 16; 8 x 3 = 24; 8 x 4 = 32; 8 x 5 = 40 Therefore, five multiples of 8 are: 8, 16, 24, 32, and 40. (c) First five multiples of 9 are: 9 x 1 = 9; 9 x 2 = 18; 9 x 3 = 27; 9 x 4 = 36; 9 x 5 = 45 Therefore, five multiples of 9 are: 9, 18, 27, 36, and 45. 3. Match the items in column 1 with the items in column 2.Column 1 Column 2
(i) 35 (a) Multiple of 8 (ii) 15 (b) Multiple of 7 (iii) 16 (c) Multiple of 70 (iv) 20 (d) Factor of 30 (v) 25 (e) Factor of 50 Solution: (i) 35 (b) Multiple of 7 (ii) 15 (d) Factor of 30 (iii) 16 (a) Multiple of 8 (iv) 20 (f) Factor of 20 (v) 25 (e) Factor of 50 4. Find all the multiples of 9 up to 100. Solution: 9 x 1 = 9 9 x 2 = 18 9 x 3 = 27 9 x 4 = 36 9 x 5 = 45 9 x 6 = 54 9 x 7 = 63 9 x 8 = 72 9 x 9 = 81 9 x 10 = 90 9 x 11 = 99 Therefore, all the multiples of 9 up to 100 are: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, and 99.CBSE Board Exam Centre List 2024
Numbers Factors
90 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 91 1, 7, 13, 91 92 1, 2, 4, 23, 46, 92 93 1, 3, 31, 93 94 1, 2, 47, 94 95 1, 5, 19, 95 96 1, 2, 3, 4, 6, 8, 12, 16, 24, 32, 4810. Express each of the following numbers as the sum of three odd primes:
(a) 21 (b) 31 (c) 53 (d) 61 Solutions: (a) 3 + 5 + 13 = 21 (b) 3 + 5 + 23 = 31 (c) 13 + 17 + 23= 53 (d) 7 + 13 + 41 = 61 11. Write five pairs of prime numbers less than 20 whose sum is divisible by 5. (Hint: 3 + 7 = 10) Solutions: The five pairs of prime numbers less than 20 whose sum is divisible by 5 are 2 + 3 = 5 2 + 13 = 15 3 + 17 = 20 7 + 13 = 20 19 + 11 = 3012. Fill in the blanks:
(a) A number with only two factors is called a ______. (b) A number with more than two factors is called a ______. (c) 1 is neither ______ nor ______. (d) The smallest prime number is ______. (e) The smallest composite number is _____. (f) The smallest even number is ______. Solutions: (a) A number with only two factors is called a prime number. (b) A number with more than two factors is called a composite number. (c) 1 is neither a prime number nor a composite number. (d) The smallest prime number is 2 (e) The smallest composite number is 4 (f) The smallest even number is 2.CBSE Syllabus Class 6 | |
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