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Ques 1: Fill up the blanks:
(i) Write all even prime numbers __________.
(ii) Number of factors of 2 are __________.
(iii) Smallest pair of coprime numbers is __________.
(iv) Smallest twin prime numbers are __________.
(v) The largest 2digit number which is odd and prime is __________.
Ans: (i) 2
(ii) two (1 and 2)
(iii) (2, 1)
(iv) 3, 5
(v) 97
Ques 2: Find the smallest number which is divisible by 2, 3, 4, and 5. Can we find the largest number which is divisible by 2, 3, 4 and 5?
Ans: 60, No
Ques 3: Write the smallest 3digit number which is exactly divisible by 6.
Ans: 102
Ques 4: Replace '*' by the smallest possible digit so that the following numbers are divisible by 3 and 9:
(i) *4129
(ii) 2*985
(iii) 987*32
Ans: (i) 2
(ii) 3
(iii) 7
Ques 5: Write the largest 3digit number which is divisible by 11.
Ans: 990
Ques 6: Find HCF of 15 m 60 cm and 20 m 16 cm.
Ans: 24 cm
Ques 7: Find the least number which when divided by 25, 40 and 60 leave the remainder 7 in each case.
Ans: 607
Ques 8: Find HCF of 90 and 243. Check if it divides 90 and 243 both.
Ans: HCF = 9, yes
Ques 9: Find LCM of 18 and 15. Check if the LCM so obtained is divisible by 15 as well as 18.
Ans: LCM = 90, yes
Ques 10: Match the following:
(i) HCF of two consecutive numbers  (a) 4 
(ii) LCM of two coprime numbers  (b) 97 
(iii) HCF of two consecutive even numbers  (c) 1 
(iv) Smallest composite number  (d) 2 
(v) Largest 2digit prime number  (e) product of two numbers 
Ans. (i) ↔ (c)
(ii) ↔ (e)
(iii) ↔ (d)
(iv) ↔ (a)
(v) ↔ (b)
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