 # What is 7/9 + 11/12? 7 9
+
 11 12

## 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 12, and get 84, then we multiply 9 by 12 and get 108. Now for the second term. You multiply 11 by 9, and get 99, then multiply 9 by 12 and get 108. We now have a new problem, that looks like this:

 84 108
+
 99 108

## Step 2

Since our denominators match, we can add the numerators.

84 + 99 = 183

That gives us the sum, which is

 183 108

## Step 3

Now, do we need to simplify this fraction?

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

Nope! So now we try the next greatest prime number, 3...

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

 183 108
÷ 3 =
 61 36

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 5...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

Nope! So now we try the next greatest prime number, 29...

Nope! So now we try the next greatest prime number, 31...

Nope! So now we try the next greatest prime number, 37...

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

There you have it! Here's the final answer to 7/9 + 11/12

 7 9
+
 11 12
=
 61 36 