Page 71 - ICSE Math 5

Exercise 5.4

1. Find the H.C.F. and L.C.M. of the following numbers. Also, verify that:

H.C.F. × L.C.M. = Product of two numbers.
(a) 440 and 520 (b) 270 and 450 (c) 84 and 108

(d) 128 and 576 (e) 603 and 609 (f) 124 and 236

2. The L.C.M. and H.C.F. of two numbers are 80 and 4 respectively. If one number is 16, find
the other number.
3. Find the H.C.F. of 84 and 216, if their L.C.M. is 1,512.

4. The product of two numbers is 360. Find the L.C.M. of two numbers, if their H.C.F. is 3.

5. The H.C.F. and L.C.M. of two numbers are 25 and 1,750 respectively. If the first number
is 250, find the second number.

6. Complete the following table.

Numbers H.C.F. L.C.M. Product of Two Numbers H.C.F. × L.C.M.

9 and 18

16 and 24

25 and 36

36 and 42

38 and 46

Review Exercise

1. Fill in the blanks.
(a) A number which is divisible by 2 and 3 is also divisible by ______________.

(b) The smallest prime number is an ______________ number.
(c) Two prime numbers are always ______________.

(d) There are ______________ pairs of twin primes in the first fifteen counting numbers.

(e) If two numbers are divisible by a number, then their sum and difference is also
______________ by that number.

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