lcm of 75 and 90

Question

show answer and how to get the answer

Answer 1

factor them first:

75 = 3 * 5 * 5

90 = 2 * 3 * 3 * 5

Take out the parts common to both of them from just one of them.  There's a 3 and a 5 in both, so take a 3 and a 5 out of the first one.  Leave the other one alone.

3 * 5 * 5 >> 5

2 * 3 * 3 * 5 >> 2 * 3 * 3 * 5

multiply the remaining stuff from both together

5 * 2 * 3 * 3 * 5 = 450

the least common multiple of 75 and 90 is 450