math help

What is 12/13 + 3/12?

What is 12/13 + 3/12?

Here's how you add

12
13
+
3
12

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

12/13 times 12

Do the same for the second term. We multiply 3 by 13, and get 39, then multiply 13 by 12 and get 156.

3/12 times 13

So now our fractions look like this:

144
156
+
39
156

Step 2

Since our denominators match, we can add the numerators.

144 + 39 = 183

So the answer is:

183
156

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...

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

183
156
÷ 3 =
61
52

Now, try the same number again.

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...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

No good. 53 is larger than 52. So we're done reducing.

Congratulations! Here's your final answer to 12/13 + 3/12

12
13
+
3
12
=
61
52
© 2014 Randy Tayler