What is the least common denominator of 1/3 and 5/12?

What is the least common denominator of 1/3 and 5/12?

• A. 6
• B. 12
• C. 3
• D. 36

Answer: (B)

The key idea is to find the smallest bottom number that both fractions can share when written with the same denominator. Here, one denominator is a multiple of the other, so the larger denominator already works for both. That makes it the least common denominator. Using that denominator lets you rewrite both fractions with the same bottom, which is what you need for adding or comparing them. The other options won’t fit because they’re either not divisible by both denominators or are larger than the smallest possible common denominator. So the correct choice is the one that uses that smallest shared denominator.

The key idea is to find the smallest bottom number that both fractions can share when written with the same denominator. Here, one denominator is a multiple of the other, so the larger denominator already works for both. That makes it the least common denominator. Using that denominator lets you rewrite both fractions with the same bottom, which is what you need for adding or comparing them. The other options won’t fit because they’re either not divisible by both denominators or are larger than the smallest possible common denominator. So the correct choice is the one that uses that smallest shared denominator.