math help

What is 1/15 + 7/8?

What is 1/15 + 7/8?

This is how we add

1
15
+
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 1 by 8, and get 8, then we multiply 15 by 8 and get 120.

1/15 times 8

Now for the second term. You multiply 7 by 15, and get 105, then multiply 15 by 8 and get 120.

7/8 times 15

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

8
120
+
105
120

Step 2

Since our denominators match, we can add the numerators.

8 + 105 = 113

That gives us the sum, which is

113
120

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...

Nope. Try the next prime number, 79...

Nope. Try the next prime number, 83...

Nope. Try the next prime number, 89...

Nope. Try the next prime number, 97...

Nope. Try the next prime number, 101...

Nope. Try the next prime number, 103...

Nope. Try the next prime number, 107...

Nope. Try the next prime number, 109...

Nope. Try the next prime number, 113...

Nope. Try the next prime number, 127...

No good. 127 is larger than 113. So we're done reducing.

Congratulations! Here's your final answer to 1/15 + 7/8

1
15
+
7
8
=
113
120
© 2014 Randy Tayler