math help

What is 12/13 + 4/12?

What is 12/13 + 4/12?

This is how to add

12
13
+
4
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 12 by 12, and get 144, then we multiply 13 by 12 and get 156.

12/13 times 12

Now for the second term. You multiply 4 by 13, and get 52, then multiply 13 by 12 and get 156.

4/12 times 13

This gives us a new problem that looks like so:

144
156
+
52
156

Step 2

Since our denominators match, we can add the numerators.

144 + 52 = 196

That gives us an answer of

196
156

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:

196
156
÷ 2 =
98
78

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:

98
78
÷ 2 =
49
39

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. So next you try the next prime number, which is 31...

No good. So next you try the next prime number, which is 37...

No good. So next you try the next prime number, which is 41...

No good. 41 is larger than 39. So we're done reducing.

And we're done! Here's the final answer to 12/13 + 4/12

12
13
+
4
12
=
49
39
© 2014 Randy Tayler