Related InterviewSolutions

• Which of the following statements are true?(a)  If a number is divisible by 3, it must be divisible by 9.(b) If a number is divisible by 9, it must be divisible by 3.(c)  A number is divisible by 18, if it is divisible by both 3 and 6.(d) If a number is divisible by 9 and 10 both, then it must be divisible by 90.(e)  If two numbers are co-primes, at least one of them must be prime.(f)  All numbers which are divisible by 4 must also be divisible by 8.g)  All numbers which are divisible by 8 must also be divisible by 4.(h)  If a number exactly divides two numbers separately, it must exactly divide their sum.(i)  If a number exactly divides the sum of two numbers, it must exactly divide the two numbers    separately.
• Write all the factors of the following numbers : (a)   24       (b)  15         (c)   21(d)  27         (e)  12         (f)   20(g)   18        (h)  23         (i)   36
• Find the LCM of 20, 25 and 30
• Find the LCM of the following numbers :(a)   9 and 4     (b)  12 and 5    (c)   6 and 5    (d)  15 and 4Observe a common property in the obtained LCMs. Is LCM the product of twonumbers in each case?
• The product of three consecutive numbers is always divisible by 6. Verify this statement with the help of some examples.
• Find the LCM of 40, 48 and 45
• Express the following as the sum of two odd primes.(a)  44        (b) 36          (c)  24           (d) 18
• The sum of two consecutive odd numbers is divisible by 4. Verify this statement with the help of some examples.
• Find the HCF of the following numbers :(a)  18, 48             (b)  30, 42                (c)  18, 60                (d) 27, 63        (e)  36, 84                        (f)   34, 102                  (g)  70, 105, 175   (h)  91, 112, 49        (i)    18, 54, 81          (j)  12, 45, 75
• What is the HCF of two consecutive(a)  numbers?        (b) even numbers?       (c) odd numbers?