How do you find the LCM for 75 and 105?

Answer 1

One way is to write out each in their prime factorization:

75 = 3x5x5

105 = 3x5x7

Write each so that common terms are directly above/below each other:

3 5 5

3 5 7

Then multiply the number in each column once:

3x5x5x7 (because there is one column of threes, two columns of fives, and one column of sevens).

Hence, the LCM of 75 and 105 is 525.