Write all the factors of :
(i) 15
(ii) 55
(iii) 48
(iv) 36
Answer
(i) Factors of 15 = 1, 3, 5 and 15
(ii) Factors of 55 = 1, 5, 11 and 55
(iii) Factors of 48 = 1, 2, 3, 4, 6, 8, 12, 16, 24 and 48
(iv) Factors of 36 = 1, 2, 3, 4, 6, 9, 12, 18 and 36
Write all the prime numbers:
(i) less than 25
(ii) between 15 and 35
(iii) between 8 and 76
Answer
A prime number is a natural number that is divisible by 1 and itself only.
(i) Prime numbers less than 25 = 2, 3, 5, 7, 11, 13, 17, 19 and 23
(ii) Prime numbers between 15 and 35 = 17, 19, 23, 29 and 31
(iii) Prime numbers between 8 and 76 = 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71 and 73
Write the prime numbers from:
(i) 5 to 45
(ii) 2 to 32
(iii) 8 to 48
Answer
A prime number is a natural number that is divisible by 1 and itself only.
(i) Prime numbers from 5 to 45 = 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41 and 43
(ii) Prime numbers from 2 to 32 = 2, 3, 5, 7, 11, 13, 17, 19, 23, 29 and 31
(iii) Prime numbers from 8 to 48 = 11, 13, 17, 19, 23, 29, 31, 37, 41, 43 and 47
Write the prime factors of:
(i) 16
(ii) 35
(iii) 49
Answer
(i) 16 = 2 × 2 × 2 × 2
∴ The prime factor of 16 is 2.
(ii) 35 = 5 × 7
∴ The prime factors of 35 are 5 and 7.
(iii) 49 = 7 × 7
∴ The prime factor of 49 is 7.