Expert: Lynn Houston - 10/12/2010

Question
How do I find the least numerator of 4/9 and 8/15?

Answer
I think maybe what you're asking for is how to find the lowest common denominator (the bottom number)?  There is no such thing as a "least numerator".  To find the lowest common denominator (lcd), factor each denominator to prime factors

9 = 3 x 3
15 = 3 x 5

Now, count the number of times each prime factor appears for each number and take the largest count.  So for 9, there are two 3's and 15 has one 3 and one 5, so you would use 3, 3 and 5.  Now, just multiply those together, 3 x 3 x 5 = 45.  45 is the lcd of 4/9 and 8/15 is 45.

Make sense?  If not, let me know and I'll give you another example.