Let me write it out because sometimes LCD could meet other things. Sign up for free to access more Fractions resources like.

## Finding common denominators

In the previous example the Least Common Multiple of 3 and 6 was 6. Follow the same steps. What Are Common Denominators? But, adding fractions with larger numbers in the denominators it can get pretty messy. Look for the smallest underlined number known as the least common multiple , or LCM.

## The Least Common Denominator

Media outlet trademarks are owned by the respective media outlets and are not affiliated with Varsity Tutors. In order to add or subtract fractions with different denominators the bottom number of the fraction , you must first find the least common denominator shared between them. Solve the rewritten problem. That looks like this:. Let me do that in a different color.

The Least Common Denominator helpwithfractions 2017-08-15T03: This is your common denominator. What makes problems like this fairly intuitive and even easy to think about is the fact that all of the fractions are written in terms of what's called a common denominator. One way to do this is to list the multiples:.

Wrap Up Okay, that's all the math we have time for today.

And that is what the Least Common Denominator is all about. That looks like this: After finding the LCD and changing the fractions accordingly, you should be able to solve the problem without further difficulty.

Since our answer is an improper fraction the numerator is larger than the denominator , we now have three options. If you have problems with any parts of this exercise, re-read the section above that covers it.

## Least Common Denominators (LCDs)

Once you have listed the factors of each denominator, circle all of the common factors. This is going to get a little detailed, so hang in there!

Varsity Tutors does not have affiliation with universities mentioned on its website. So we factor each number into primes. In this example, the denominators only share one multiple and it is 30: The answer will be a mixed number. Common denominators review. If not, please review how to deal with improper fractions.