 # What is 4/12 + 2/7? Here's how we add

 4 12
+
 2 7

## 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 4 by 7, and get 28, then we multiply 12 by 7 and get 84. Now for the second term. You multiply 2 by 12, and get 24, then multiply 12 by 7 and get 84. This gives us a new problem that looks like so:

 28 84
+
 24 84

## Step 2

Since our denominators match, we can add the numerators.

28 + 24 = 52

That gives us an answer of

 52 84

## Step 3

Can this fraction be reduced?

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

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

 52 84
÷ 2 =
 26 42

Now, try the same number again.

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

 26 42
÷ 2 =
 13 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...

No good. 17 is larger than 13. So we're done reducing.

Congratulations! Here's your final answer to 4/12 + 2/7

 4 12
+
 2 7
=
 13 21
© 2014 Randy Tayler