math help

What is 15/11 + 6/9?

What is 15/11 + 6/9?

This is how to add

15
11
+
6
9

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 15 by 9, and get 135, then we multiply 11 by 9 and get 99.

15/11 times 9

Now for the second term. You multiply 6 by 11, and get 66, then multiply 11 by 9 and get 99.

6/9 times 11

This gives us a new problem that looks like so:

135
99
+
66
99

Step 2

Since our denominators match, we can add the numerators.

135 + 66 = 201

That gives us an answer of

201
99

Step 3

Can this fraction be reduced?

First, we attempt to divide it by 2...

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:

201
99
÷ 3 =
67
33

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. 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. 37 is larger than 33. So we're done reducing.

And we're done! Here's the final answer to 15/11 + 6/9

15
11
+
6
9
=
67
33
© 2014 Randy Tayler