math help

What is 15/60 + 1/7?

What is 15/60 + 1/7?

This is how to add

15
60
+
1
7

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 15 by 7, and get 105, then we multiply 60 by 7 and get 420.

15/60 times 7

Now for the second term. You multiply 1 by 60, and get 60, then multiply 60 by 7 and get 420.

1/7 times 60

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

105
420
+
60
420

Step 2

Since our denominators match, we can add the numerators.

105 + 60 = 165

Answer:

165
420

Step 3

Now, do we need to simplify this fraction?

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:

165
420
÷ 3 =
55
140

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:

55
140
÷ 5 =
11
28

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. 13 is larger than 11. So we're done reducing.

And we're done! Here's the final answer to 15/60 + 1/7

15
60
+
1
7
=
11
28
© 2014 Randy Tayler