# How can greatest common factor and least common multiples help you work with fractions?

The GCF helps in simplifying fractions and the LCM helps in adding and subtracting them.

### What is the greatest common multiple of 9 and 27?

Common Multiples are multiples which are common to both numbers So Multiples of 9 are 9, 18, 27, 36 etc... Multiples of 27 are 27, 54, 81 etc... you can work out the least common multiple as 27 We can see that 9 is a factor of 27 so all multiples of 27 are a common multiple with 9. But as there is no upper limit we can not work out a greatest common multiple…