What is 1/5 + 3/7?

This is how you add

Step 1

We 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 7, and get 7, then we multiply 5 by 7 and get 35.

Do the same for the second term. We multiply 3 by 5, and get 15, then multiply 5 by 7 and get 35.

So now our fractions look like this:

Step 2

Since our denominators match, we can add the numerators.

7 + 15 = 22

So the answer is:

Step 3

Last 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...

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...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

No good. 23 is larger than 22. So we're done reducing.

Congratulations! Here's your final answer to 1/5 + 3/7