math help

What is 78/92 + 9/12?

What is 78/92 + 9/12?

This is how you add

78
92
+
9
12

Step 1

Can you add yet? Nope! The denominators don't match. We need a common denominator. So next we take both denominators and multiply them. Next, take each numerator and multiply it by the denominator of the other term.

So, we multiply 78 by 12, and get 936, then we multiply 92 by 12 and get 1104.

78/92 times 12

Now for the second term. You multiply 9 by 92, and get 828, then multiply 92 by 12 and get 1104.

9/12 times 92

We now have a new problem, that looks like this:

936
1104
+
828
1104

Step 2

Since our denominators match, we can add the numerators.

936 + 828 = 1764

That gives us the sum, which is

1764
1104

Step 3

Now, do we need to simplify this fraction?

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

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

1764
1104
÷ 2 =
882
552

So far so good... let's try to divide by that number again.

Are both the numerator and the denominator evenly divisible by 2? Yes! So we reduce it:

882
552
÷ 2 =
441
276

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 3...

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

441
276
÷ 3 =
147
92

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. 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. 97 is larger than 92. So we're done reducing.

And we're done! Here's the final answer to 78/92 + 9/12

78
92
+
9
12
=
147
92
© 2014 Randy Tayler