 # What is 4/12 + 6/9? This is how we add

 4 12
+
 6 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 4 by 9, and get 36, then we multiply 12 by 9 and get 108. Now for the second term. You multiply 6 by 12, and get 72, then multiply 12 by 9 and get 108. We now have a new problem, that looks like this:

 36 108
+
 72 108

## Step 2

Since our denominators match, we can add the numerators.

36 + 72 = 108

That gives us the sum, which is

 108 108

## 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:

 108 108
÷ 2 =
 54 54

Now, try the same number again.

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

 54 54
÷ 2 =
 27 27

Now, try the same number again.

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

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

 27 27
÷ 3 =
 9 9

Now, try the same number again.

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

 9 9
÷ 3 =
 3 3

Now, try the same number again.

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

 3 3
÷ 3 =
 1 1

Now, try the same number again.

No good. 3 is larger than 1. So we're done reducing.

Congratulations! Here's your final answer to 4/12 + 6/9

 4 12
+
 6 9
=
 1 1
= 1
© 2014 Randy Tayler