the common denominator for 9/8 and 7/20 is 40. (45/40 and 14/40)
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.
The least common multiple is the smallest positive number that is the multiple two or more numbers. 18: 18, 36, 54, 72, 90 30: 30, 60, 90 45: 45, 90 The LCM of 18, 30 and 45 is 90.
360
Finding The Least Common DenominatorThe least common denominator of two or more non-zerodenominators is actually the smallest whole number that is divisible by each of the denominators. Actually, this is the same basic idea behind finding the Least Common Multiple (LCM) for whole numbers (without the fractional parts).To find the least common denominator, simply list the multiples of each denominator (multiply by 2, 3, 4, etc.) then look for the smallest number that appears in each list.Example: Suppose we wanted to add 1/5 + 1/6 + 1/15. We would find the least common denominator as follows...First we list the multiples of each denominator.Multiples of 5 are 10, 15, 20, 25, 30, 35, 40,...Multiples of 6 are 12, 18, 24, 30, 36, 42, 48,...Multiples of 15 are 30, 45, 60, 75, 90,....Now, when you look at the list of multiples, you can see that 30 is the smallest number that appears in each list.Therefore, the least common denominator of 1/5, 1/6 and 1/15 is 30.This method works pretty good. But, in adding fractions with larger numbers in the denominators can get pretty messy. Again, see the Related Link for another way to find a least common denominator.
The greatest common denominator is infinite. The least common denominator is 45.
The least common multiple is 1440
If I wanted to be nasty about it, I would say 1, because the least common denominator of 45/1 and 75/1 is 1. The least common denominator of two fractions is the least common multiple of their denominators. I presume you are asking for the least common multiple of 45 and 75, which is 225.
45
45
30=2x3x5 45=3x3x5 2x3x3x5=90 The lowest common multiple.
15
360
45
It is: 45
20
The Least Common Multiple (LCM) for 30 45 is 90.