 # What is 1/7 + 2/4? 1 7
+
 2 4

## Step 1

Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator.

Now you multiply 1 by 4, and get 4, then we multiply 7 by 4 and get 28. Do the same for the second term. We multiply 2 by 7, and get 14, then multiply 7 by 4 and get 28. The problem now has new fractions to add:

 4 28
+
 14 28

## Step 2

Since our denominators match, we can add the numerators.

4 + 14 = 18

The sum we get is

 18 28

## Step 3

The last step is to reduce the fraction if we can.

To find out, we try dividing it by 2...

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

 18 28
÷ 2 =
 9 14

So far so good... let's try to divide by that number again.

No good. So next you try the next prime number, which is 3...

No good. So next you try the next prime number, which is 5...

No good. So next you try the next prime number, which is 7...

No good. So next you try the next prime number, which is 11...

No good. 11 is larger than 9. So we're done reducing.

And we're done! Here's the final answer to 1/7 + 2/4

 1 7
+
 2 4
=
 9 14