math help

What is 12/13 + 9/10?

What is 12/13 + 9/10?

This is how you add

12
13
+
9
10

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 10, and get 120, then we multiply 13 by 10 and get 130.

12/13 times 10

Do the same for the second term. We multiply 9 by 13, and get 117, then multiply 13 by 10 and get 130.

9/10 times 13

So now our fractions look like this:

120
130
+
117
130

Step 2

Since our denominators match, we can add the numerators.

120 + 117 = 237

Now we have an answer.

237
130

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. 131 is larger than 130. So we're done reducing.

And we're done! Here's the final answer to 12/13 + 9/10

12
13
+
9
10
=
237
130
© 2014 Randy Tayler