math help

What is 15/60 + 3/11?

What is 15/60 + 3/11?

Here's how you add

15
60
+
3
11

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 15 by 11, and get 165, then we multiply 60 by 11 and get 660.

15/60 times 11

Now for the second term. You multiply 3 by 60, and get 180, then multiply 60 by 11 and get 660.

3/11 times 60

This gives us a new problem that looks like so:

165
660
+
180
660

Step 2

Since our denominators match, we can add the numerators.

165 + 180 = 345

That gives us an answer of

345
660

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:

345
660
÷ 3 =
115
220

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...

Are both the numerator and the denominator evenly divisible by 5? Yes! So we reduce it:

115
220
÷ 5 =
23
44

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 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. 29 is larger than 23. So we're done reducing.

And we're done! Here's the final answer to 15/60 + 3/11

15
60
+
3
11
=
23
44
© 2014 Randy Tayler