 # What is 7/12 + 7/9? 7 12
+
 7 9

## Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 7 by 9, and get 63, then we multiply 12 by 9 and get 108. Now for the second term. You multiply 7 by 12, and get 84, then multiply 12 by 9 and get 108. We now have a new problem, that looks like this:

 63 108
+
 84 108

## Step 2

Since our denominators match, we can add the numerators.

63 + 84 = 147

 147 108

## Step 3

Now, do we need to simplify this fraction?

First, we attempt to divide it by 2...

No good. So next you try the next prime number, which is 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

 147 108
÷ 3 =
 49 36

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 5...

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. So next you try the next prime number, which is 13...

No good. So next you try the next prime number, which is 17...

No good. So next you try the next prime number, which is 19...

No good. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. 37 is larger than 36. So we're done reducing.

And we're done! Here's the final answer to 7/12 + 7/9

 7 12
+
 7 9
=
 49 36