math help

What is 12/13 + 7/12?

What is 12/13 + 7/12?

This is how you add

12
13
+
7
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 7 by 13, and get 91, then multiply 13 by 12 and get 156.

7/12 times 13

So now our fractions look like this:

144
156
+
91
156

Step 2

Since our denominators match, we can add the numerators.

144 + 91 = 235

Now we have an answer.

235
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...

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. So next you try the next prime number, which is 43...

No good. So next you try the next prime number, which is 47...

No good. So next you try the next prime number, which is 53...

No good. So next you try the next prime number, which is 59...

No good. So next you try the next prime number, which is 61...

No good. So next you try the next prime number, which is 67...

No good. So next you try the next prime number, which is 71...

No good. So next you try the next prime number, which is 73...

No good. So next you try the next prime number, which is 79...

No good. So next you try the next prime number, which is 83...

No good. So next you try the next prime number, which is 89...

No good. So next you try the next prime number, which is 97...

No good. So next you try the next prime number, which is 101...

No good. So next you try the next prime number, which is 103...

No good. So next you try the next prime number, which is 107...

No good. So next you try the next prime number, which is 109...

No good. So next you try the next prime number, which is 113...

No good. So next you try the next prime number, which is 127...

No good. So next you try the next prime number, which is 131...

No good. So next you try the next prime number, which is 137...

No good. So next you try the next prime number, which is 139...

No good. So next you try the next prime number, which is 149...

No good. So next you try the next prime number, which is 151...

No good. So next you try the next prime number, which is 157...

No good. 157 is larger than 156. So we're done reducing.

And we're done! Here's the final answer to 12/13 + 7/12

12
13
+
7
12
=
235
156
© 2014 Randy Tayler