math help

What is 15/60 + 4/11?

What is 15/60 + 4/11?

This is how to add

15
60
+
4
11

Step 1

Of course, you can't add two fractions if the denominators (bottom numbers) don't match. To get a common denominator, multiply the denominators together. Then we fix the numerators by multiplying each one by their other term's denominator.

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

15/60 times 11

Do the same for the second term. We multiply 4 by 60, and get 240, then multiply 60 by 11 and get 660.

4/11 times 60

The problem now has new fractions to add:

165
660
+
240
660

Step 2

Since our denominators match, we can add the numerators.

165 + 240 = 405

This yields the answer

405
660

Step 3

The last step is to reduce the fraction if we can.

To find out, we try dividing it by 2...

Nope! So now we try the next greatest prime number, 3...

Are both the numerator and the denominator evenly divisible by 3? Yes! So we reduce it:

405
660
÷ 3 =
135
220

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 5...

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

135
220
÷ 5 =
27
44

Let's try dividing by that again...

Nope! So now we try the next greatest prime number, 7...

Nope! So now we try the next greatest prime number, 11...

Nope! So now we try the next greatest prime number, 13...

Nope! So now we try the next greatest prime number, 17...

Nope! So now we try the next greatest prime number, 19...

Nope! So now we try the next greatest prime number, 23...

Nope! So now we try the next greatest prime number, 29...

No good. 29 is larger than 27. So we're done reducing.

There you have it! Here's the final answer to 15/60 + 4/11

15
60
+
4
11
=
27
44
© 2014 Randy Tayler