Question

Find the L.C.M. of each the following groups of numbers, using

(i) the prime factor method and

(ii) the common division method :

(i) 18, 24 and 96

(ii) 100, 150 and 200

(iii) 14, 21 and 98

(iv) 22, 121 and 33

(v) 34, 85 and 51

Answer 1

(i) L.C.M. of 18, 24 and 96

(i) By prime factors

Prime factors of 18 = 2 x 3 x 3

Prime factors of 24 = 2 x 2 x 2 x 3

Prime factors of 96 = 2 x 2 x 2 x 2 x 2 x 3

L.C.M. = 2 x 2 x 2 x 2 x 2 x 3 x 3 = 288

By common division method

L.C.M. of 18, 24 and 96 = 2 x 2 x 2 x 3 x 3 x 4 = 288

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

= 2 x 2 x 5 x 5 x 3 x 2 = 600 

Common division method: