Question

Find the L.C.M. of the following group of numbers, using

1. the prime factor method and
2. the common division method

100, 150 and 200

Answer 1

L.C.M. of 100, 150 and 200

i. By prime factors
Prime factors of 100 = 2 x 2 x 5 x 5 = 2² x 5²
Prime factors of 150 = 2 x 3 x 5 x 5 = 2¹ x 3¹ x 5²
Prime factors of 200 = 2 x 2 x 2 x 5 x 5 = 2³ x 5²
∴ L.C.M. of 100, 150 and 200 = 2³ x 3¹ x 5² = 600

ii. By common division method

2	100,	150,	200
2	50,	75,	100
5	25,	75,	50
5	5,	15,	10
	1,	3,	2

∴ L.C.M. of 100, 150 and 200 = 2 x 2 x 5 x 5 x 3 x 2 = 600