math help

What is 31/12 + 5/8?

What is 31/12 + 5/8?

Here's how to add

31
12
+
5
8

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 31 by 8, and get 248, then we multiply 12 by 8 and get 96.

31/12 times 8

Do the same for the second term. We multiply 5 by 12, and get 60, then multiply 12 by 8 and get 96.

5/8 times 12

So now our fractions look like this:

248
96
+
60
96

Step 2

Since our denominators match, we can add the numerators.

248 + 60 = 308

So the answer is:

308
96

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...

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

308
96
÷ 2 =
154
48

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

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

154
48
÷ 2 =
77
24

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. 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. So next you try the next prime number, which is 23...

No good. So next you try the next prime number, which is 29...

No good. 29 is larger than 24. So we're done reducing.

And we're done! Here's the final answer to 31/12 + 5/8

31
12
+
5
8
=
77
24
© 2014 Randy Tayler