math
posted by joe on .
what's the LCM of 9 and 15?
I got 9
is that the correct answer?

No.
Multiples of 9 are: 9, 18, 27, 36, 45, 54, 63
Multiples of 15 are: 15, 30, 45, 60, 75
What is the smallest number that is a multiple of both numbers?
http://www.math.com/school/subject1/lessons/S1U3L3GL.html 
45?

Right. 45 is the LCM of 9 and 15.