This is how to add


Step 1We can't add two fractions with different denominators (the bottom number). So you need to get a common denominator  both bottom numbers need to match. To do this, you'll multiply the denominators times each other... but the numerators have to change, too. They get multiplied by the other term's denominator. So we multiply 1 by 11, and get 11, then we multiply 7 by 11 and get 77. Do the same for the second term. We multiply 1 by 7, and get 7, then multiply 7 by 11 and get 77. So now our fractions look like this:


Step 2Since our denominators match, we can add the numerators. 11 + 7 = 18 Now we have an answer.


Step 3Last of all, we need to simplify the fraction, if possible. Can it be reduced to a simpler fraction? To find out, we try dividing it by 2... 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. So next you try the next prime number, which is 13... No good. So next you try the next prime number, which is 17... No good. So next you try the next prime number, which is 19... No good. 19 is larger than 18. So we're done reducing. And we're done! Here's the final answer to 1/7 + 1/11
