What is the LCM of 85 and 90?

Answer 1

To find the LCM of two numbers you first have to split them into their prime factors. In this case:

85=5x17

90=5x3x3x2

The next step is to identify any common prime factors, and ignore one of the pair. In this case, both numbers have one 5 as a prime factor, so we can ignore one of the 5s. Take all the other numbers:

5,17,3,3,2

And find the product:

5x17x3x3x2=1,530

Thus the LCM of 85 and 90 is 1,530