What is the least common denominator for 9 and 15?

Answer 1

least common demonminator of 15 and 9 is 45.

Answer 2

The least common denominator of 9 and 15 (if they are denominators) is the least common multiple of those numbers.

We denote this the LCD. One way to find that is write the prime factorization of the two numbers.

9 = 3^2

15 = 3 x 5

Take 3^2 x 5 = 9 x 5 or 45 is the LCM of 9 and 15. This is the product of the primes with the largest exponents.

So the LCD or least common denominator is the LCM of 9 and 15 and this is 45.