# How do you write fractions with a common denominator?

##### 1 Answer

To write fractions with a common denominator, you will most likely need to scale some numbers up! I will explain how.

Let's try it with the fractions

12 is larger than 3, so we will have to multiply the 3 by some number to equal 12. (We are really finding the Least Common Multiple of the two denominators!) To do this, you have to multiply the 3 by 4, because 3x4=12. But now the numerator doesn't match the denominator. When you scale the denominator up, you have to scale the numerator up too! So the 2 must be multiplied by 4 also.

Now you have the following:

These fractions now have common denominators! Now they're all set for adding or subtracting fractions.

Try another:

Transform each fraction by multiplying by "1":

One last problem:

Hope this helped!