math help

What is 1/15 + 2/7?

What is 1/15 + 2/7?

Here's how we add

1
15
+
2
7

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 1 by 7, and get 7, then we multiply 15 by 7 and get 105.

1/15 times 7

Now for the second term. You multiply 2 by 15, and get 30, then multiply 15 by 7 and get 105.

2/7 times 15

This gives us a new problem that looks like so:

7
105
+
30
105

Step 2

Since our denominators match, we can add the numerators.

7 + 30 = 37

That gives us an answer of

37
105

Step 3

Can this fraction be reduced?

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...

No good. 41 is larger than 37. So we're done reducing.

Congratulations! Here's your final answer to 1/15 + 2/7

1
15
+
2
7
=
37
105
© 2014 Randy Tayler