math help

What is 7/9 + 7/8?

What is 7/9 + 7/8?

This is how we add

7
9
+
7
8

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 7 by 8, and get 56, then we multiply 9 by 8 and get 72.

7/9 times 8

Now for the second term. You multiply 7 by 9, and get 63, then multiply 9 by 8 and get 72.

7/8 times 9

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

56
72
+
63
72

Step 2

Since our denominators match, we can add the numerators.

56 + 63 = 119

That gives us the sum, which is

119
72

Step 3

Now, do we need to simplify this fraction?

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

Nope. Try the next prime number, 3...

Nope. Try the next prime number, 5...

Nope. Try the next prime number, 7...

Nope. Try the next prime number, 11...

Nope. Try the next prime number, 13...

Nope. Try the next prime number, 17...

Nope. Try the next prime number, 19...

Nope. Try the next prime number, 23...

Nope. Try the next prime number, 29...

Nope. Try the next prime number, 31...

Nope. Try the next prime number, 37...

Nope. Try the next prime number, 41...

Nope. Try the next prime number, 43...

Nope. Try the next prime number, 47...

Nope. Try the next prime number, 53...

Nope. Try the next prime number, 59...

Nope. Try the next prime number, 61...

Nope. Try the next prime number, 67...

Nope. Try the next prime number, 71...

Nope. Try the next prime number, 73...

No good. 73 is larger than 72. So we're done reducing.

Congratulations! Here's your final answer to 7/9 + 7/8

7
9
+
7
8
=
119
72
© 2014 Randy Tayler