10 and 21, 5 and 42, 14 and 15, 2 ans 105 ect.
Since they have no common prime factors, multiply them together.3 x 7 x 10 = 210, the LCM
210 and 420 have a GCF of 210.
2 x 3 x 5 x 7 2 x 3 = 6 6 x 5 = 30 30 x 7 = 210 2 x 3 x 5 x 7 = 210
210 6*35 is 210, 42 *5 is 210, and 21 *10 is 210
the answer to the question 'what is the LCM of 3,7,10 is 210