math help

What is 31/12 + 2/8?

What is 31/12 + 2/8?

Here's how we add

31
12
+
2
8

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

31/12 times 8

Now for the second term. You multiply 2 by 12, and get 24, then multiply 12 by 8 and get 96.

2/8 times 12

This gives us a new problem that looks like so:

248
96
+
24
96

Step 2

Since our denominators match, we can add the numerators.

248 + 24 = 272

So what's the answer so far?

272
96

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:

272
96
÷ 2 =
136
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:

136
48
÷ 2 =
68
24

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:

68
24
÷ 2 =
34
12

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:

34
12
÷ 2 =
17
6

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. 7 is larger than 6. So we're done reducing.

And we're done! Here's the final answer to 31/12 + 2/8

31
12
+
2
8
=
17
6
© 2014 Randy Tayler