 # What is 4/7 + 8/12? 4 7
+
 8 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 4 by 12, and get 48, then we multiply 7 by 12 and get 84. Now for the second term. You multiply 8 by 7, and get 56, then multiply 7 by 12 and get 84. We now have a new problem, that looks like this:

 48 84
+
 56 84

## Step 2

Since our denominators match, we can add the numerators.

48 + 56 = 104

That gives us the sum, which is

 104 84

## Step 3

Now, do we need to simplify this fraction?

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

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

 104 84
÷ 2 =
 52 42

Now, try the same number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

 52 42
÷ 2 =
 26 21

Now, try the same number again.

Nope. Try the next prime number, 3...

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

No good. 23 is larger than 21. So we're done reducing.