math help

What is 91/6 + 7/9?

What is 91/6 + 7/9?

Let's add

91
6
+
7
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 91 by 9, and get 819, then we multiply 6 by 9 and get 54.

91/6 times 9

Now for the second term. You multiply 7 by 6, and get 42, then multiply 6 by 9 and get 54.

7/9 times 6

This gives us a new problem that looks like so:

819
54
+
42
54

Step 2

Since our denominators match, we can add the numerators.

819 + 42 = 861

That gives us an answer of

861
54

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:

861
54
÷ 3 =
287
18

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. 19 is larger than 18. So we're done reducing.

And we're done! Here's the final answer to 91/6 + 7/9

91
6
+
7
9
=
287
18
© 2014 Randy Tayler