CLASS-5
FINDING HCF & LCM OF SAME NUMBERS

To find out the HCF we have to depend on common factors only.

So, in the divisional method there are no other common factors except 5, 5. The remaining factors 3, 5 & 1 are co-prime numbers, so there only common factors are one ‘1’.

So, the HCF is 5 x 5 = 25, HCF of 75, 125 & 25 is 25.

To find the LCM we have to depend on not only Common factors even remaining factors also.

So, LCF of the numbers 75, 125 and 25 is = 5 x 5 x ( 3 x 5 x 1 ) = 375

So, HCF & LCM of the numbers 75, 125 & 25 are 25 & 375 respectively.        (Ans.)

2) Find HCF & LCM of  80, 60, 120.

To find out the HCF we have to depend on common factors only

So, in the divisional method there are no other common factors except 2, 2, 5, 2, 3. The remaining factors 2, 1 & 1 are co-prime numbers, so there only common factors are one ‘1’.

So, the HCF is 2 x 2 x 5 x 2 x 3 = 120, HCF of 80, 60 & 120 is 120.

To find the LCM, we have to depend on not only Common factors even remaining factors also.

So, LCM of the numbers 80, 60 and 120 is = 2 x 2 x 5 x 2 x 3 x (2 x 1 x 1) = 240

So, HCF & LCM of the numbers 80, 60 & 120 are 120 & 240 respectively.       (Ans.)