 # What is 1/12 + 3/9? 1 12
+
 3 9

## Step 1

We still have different denominators (bottom numbers), though, so we need to get a common denominator. This will make the bottom numbers match. Multiply the denominators together first. Now, multiply each numerator by the other term's denominator.

Now we multiply 1 by 9, and get 9, then we multiply 12 by 9 and get 108. Now for the second term. You multiply 3 by 12, and get 36, then multiply 12 by 9 and get 108. This gives us a new problem that looks like so:

 9 108
+
 36 108

## Step 2

Since our denominators match, we can add the numerators.

9 + 36 = 45

That gives us an answer of

 45 108

## Step 3

Can this fraction be reduced?

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

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

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

 45 108
÷ 3 =
 15 36

Now, try the same number again.

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

 15 36
÷ 3 =
 5 12

Now, try the same number again.

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

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

No good. 7 is larger than 5. So we're done reducing.