math help

What is 3/18 + 8/12?

What is 3/18 + 8/12?

This is how to add

3
18
+
8
12

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 3 by 12, and get 36, then we multiply 18 by 12 and get 216.

3/18 times 12

Now for the second term. You multiply 8 by 18, and get 144, then multiply 18 by 12 and get 216.

8/12 times 18

This gives us a new problem that looks like so:

36
216
+
144
216

Step 2

Since our denominators match, we can add the numerators.

36 + 144 = 180

That gives us an answer of

180
216

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:

180
216
÷ 2 =
90
108

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:

90
108
÷ 2 =
45
54

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...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

45
54
÷ 3 =
15
18

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

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

15
18
÷ 3 =
5
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 5...

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

No good. 7 is larger than 5. So we're done reducing.

And we're done! Here's the final answer to 3/18 + 8/12

3
18
+
8
12
=
5
6
© 2014 Randy Tayler