What is the LCM of 49 35 21 and 15?

Answer 1

The LCM is the product of the highest power of each prime factor.

Express each number in terms of its prime factors.

49 = 7 x 7 = 72

35 = 5 x 7

21 = 3 x 7

15 = 3 x 5

The highest power of 3 is just 3, of 5 is just 5 and of 7 is 72.

The LCM is thus 3 x 5 x 72 = 735