# CLASS-5LOWEST COMMON MULTIPLICATION (LCM)

LOWEST COMMON MULTIPLICATION (LCM)

Finding LCM through common multiplication method-

1) Find out the common multiplication (LCM) of three numbers 5 , 3 ,10 through the multipliers method

Ans.) Common multiplier of 5 are – 5, 10, 15, 20, 25, 30, 35, 40, 45, 50.

Common multiplier of 3 are – 3, 6, 9, 12, 15, 18, 21, 24, 27, 30.

Common multiplier of 10 are – 10, 20, 30, 40, 50, 60, 70, 80, 90, 100.

We can conclude that, 30 is the lowest (least) common multiplication of these three numbers.

2) Find out the common multiplication (LCM) of three numbers 3 , 4 , 6 through the multipliers method

Ans.)  Common multiplier of 3 are – 3, 6, 9, 12, 15, 18, 21, 24, 27, 30.

Common multiplier of 4 are – 4, 8, 12, 16, 20, 24, 28, 32, 36, 40.

Common multiplier of 6 are – 6, 12, 18, 24, 30, 36, 42, 48, 54, 60.

We can conclude that, 24 is the lowest (least) common multiplication of these three numbers.

LCM by Prime Factorization –

1) Find out the Lowest common multiplication (LCM) of three numbers 18, 24, 12 through prime factorization.

Ans.)   Prime factorization of 18 = 2 x 3 x 3

Prime factorization of 24 = 2 x 2 x 2 x 3

Prime factorization of 12 = 2 x 2 x 3

So, multiplying common factor of 2 , 3 and other remaining prime factor, we can get the LCM of prime factorization, that is  LCM = 2 x 3 x 3 x 2 x 2 x 2 =144.   (Ans.)